Cadillac introduced the relatively compact Seville three decades ago in response to surging Mercedes sales. Although it stole few customers from Mercedes, the car sold well to traditional luxury car buyers seeking a more manageable package. The second and third generation Sevilles did not fare so well. The second suffered from controversial rear-end styling (the infamous “bustleback”) while the third suffered from nondescript styling and a cramped rear seat. The larger, more rakishly styled fourth generation Seville was the first that truly deserved comparison to a Mercedes. Especially after it gained a DOHC V8 in its second model year. A fifth-generation sedan was a refinement of the fourth.

Despite this progress with the Seville, Cadillac sales continued to decline while Mercedes sales continued to grow, such that in the late 1990s the latter passed the former. In the mid-70s Mercedes represented a minor threat. Today it along with Lexus and BMW threaten to put Cadillac out of the luxury car business altogether. By the late 1990s it became clear to GM that the brand’s twenty-first century products would have to be radically different from and far better than the Sevilles and DeVilles of the 1990s. The board anted up five billion dollars. The 2003 CTS was the first of the resulting new generation of vehicles. It was good enough to warrant comparison to compact German sedans. The 2004 SRX and XLR similarly earned good reviews.

But what Cadillac really needs is a strong contender in the midsize luxury sedan segment. The images (and profitability) of Mercedes and BMW are heavily dependent on the sedans at the center of their lines, the E-Class and 5-Series, respectively. Cadillac needed a similar anchor product.

And so the stakes are high with the new-for-2005 sixth-gen Seville, renamed STS. After arguing for a decade or two that a front-drive sedan can compete in this class, Cadillac decided to join ‘em. Like the smaller CTS with which it shares a basic architecture, the STS is rear-wheel-drive. (If today’s stability control systems are insufficient for your peace of mind, all-wheel-drive is optional.) Also like the German sedans, a DOHC six-cylinder is standard, while a DOHC eight is optional. Inside, the STS looks more German than any previous Cadillac.

So at first glance Cadillac now has a true competitor in the heart of the luxury sedan market. But what about after a thorough test drive?

I waited until my father was in town to take this test drive, as he much better represents the market for this car. His current car is a Lexus GS 400, and before that he owned an LS 400. Could the STS win him back to an American brand?

Styling

The STS looks much like a stretched CTS with edges smoothed off and most of the smaller sedan’s many creases ironed out. Unfortunately, adding those inches and taking away those edges and creases results it a much less interesting design. In the most evident change from the CTS, the front and rear lamps don't kink into the fenders on the STS. As a result the car's corners have the overly square, drab, somehow Stalinist look that also afflicts Mitsubishi's Galant.

The STS looks especially blah around the C-pillar and rear fender. Seventeen-inch alloys have never looked so tiny. Almost temporary spare tiny. Lots of air both vertically and horizontally around the rear base tire. Why? Has the basic car been shortchanged so huge tires and wheels can be fitted to a low-volume, high-performance STSv down the road? The 1SG package’s 18-inch wheels help—but that’s a $13,000 package.

Certainly far fewer people will dislike the styling of the STS than have disliked that of the CTS. But also far fewer will love it. I doubt more than one out of five people who see this car on the road will even recognize they’re seeing Cadillac’s new standard bearer. People noticed the CTS. A real disappointment.

Inside Cadillac has similarly taken far fewer stylistic chances with the STS than with the CTS and SRX. The instrument and door panels are thoroughly conventional. The materials are generally appropriate for a $50,000 car. The main exception is the use of hard plastic on the center console. For hard plastic it looks and feels high in quality, but you touch it all the time and will never mistake it for anything but hard plastic. I’ve been similarly let down by the relatively pedestrian ambiance of the current E-Class interior. To me, the interior of the Lexus LS 430 looks and feels far richer than either. Cadillac benchmarked the wrong target in this area.

Accommodations

The driving position is very good, neither too low nor too high relative to the instrument panel. The pillars and header do not overly intrude. The wheel has power adjustments for tilt and telescope. One nit: the power tilt is very quick, so small adjustments can be difficult. Why?

The front seats are reasonably comfortable, but lack the instantly evident outstanding comfort of those in the big Lexus and the Swedish flagships. For aggressive drivers lateral support is deficient, except possibly for those especially broad of beam.

The rear seat is another major disappointment. The STS is larger and more expensive than the CTS, but if anything its rear seat feels more cramped and is less comfortable. While headroom is ample, knee room behind the front seats and toe room beneath them are both in short supply. Adult men will fit, but with little room to spare. And they won’t be comfortable, as the cushion is too low to the floor to provide thigh support.

The trunk is about average in size for this class of car. But be aware that—unlike in the CTS, E-Class, and 5-Series—a folding rear seat is not available.

On the Road

In the past the styling and spec sheets of American luxury sedans have often promised better performance than the cars delivered. In the case of the STS, we have the opposite. The predominate impression I took from the test drive was of thorough refinement. The STS glides smoothly, almost liquidly over just about any pavement, at any reasonable speed. I drove the car over stretches of rough pavement that produce much thumping and jostling in the average car. They were barely heard or felt in the STS.

And this is not simply the product of a very soft suspension. The STS’ chassis remains composed over the rough stuff. This is perhaps the most impressive aspect of the car.

Noise levels even at 90 miles per hour remain low. My father felt that the STS was quieter than the Lexus GS and very nearly a match for the LS.

This refinement extends to the engine. At idle it is nearly silent, and even at full throttle the noise level remains moderate. (Well, my father called it “loud,” but this was only relative to the otherwise near silence of the car.) Earlier Northstar V8s sounded too similar to traditional, less sophisticated American V8s for my taste. This third-generation unit still has a lower engine note than the typical import V8, but the overall sound is just as refined. It now sounds like the DOHC V8 it is. The noise you do hear you’ll enjoy hearing.

The Northstar V8 has always been powerful. That said, I was unimpressed by the power delivery of first and second generation units. They felt soft to me until the tach hit 4,000 or so, where they took off with a roar. There was an obvious source of this issue: GM had decided not to gift the engine with variable valve timing to minimize cost and complexity. They reasoned that a few hundred more cubic centimeters than competing V8s would more than compensate.

Well, peak power is one thing, the shape of the torque curve another. If it has a plumper torque curve, a 150-horsepower engine can feel thrustier around town than a 300-horsepower engine.

With the latest redesign of the Northstar GM finally bit the bullet and included variable valve timing. Though the specs suggest little improvement—the torque curve still peaks at a moderately lofty (for this size engine) 4400 RPM—the revised engine’s midrange feels significantly plumper.

It helps that the engine is finally paired with a five-speed automatic (and a six-speed is on the way). GM made do with a four-speed transmission for far too long, and the widely-spaced ratios of that transmission were not a good fit with the Northstar engine.

I drove the 320-horsepower V8, but based on my experience in the CTS the 255-horsepower V6 is also an excellent engine. Even in the heavier STS it should be plenty powerful for most buyers. And it is at least as refined as the eight.

So far, so good enough. Now we come to my main issue with the STS’ performance: the steering. Although the suspension is generally excellent, with a balanced feel and a reasonable amount of lean in hard turns, I never felt confident driving this car. The steering is quick, but lacking in feedback. It feels especially soft, even “loose” (as my Lexus-driving father described it), just off center. Deciding how much to turn the wheel is an affair of trial and error. It should be intuitive. Like in the Mercedes S-Class, a larger sedan that drives like a smaller one.

A steering system made by ZF, purveyor to BMW (among others), is part of the priciest option package for both V6 and V8 cars. It might help. The dealer only had one STS so fitted, and it had been preordered by a customer. Few dealers are likely to stock such cars, as they are pricey. (The sold 1SG STS on the lot listed for $60,600.) Bottom line: I cannot tell you whether the ZF steering corrects this issue, and don’t know when or even if I will be able to.

Frankly, GM should be able to produce a first-class steering system without relying on a German supplier. In GM car after GM car the steering system has been my largest complaint. (At least the STS isn’t fitted with the abysmal electric-assist system that plagues the Malibu, G6, ION, and VUE.) The car guys are supposedly back in the saddle at GM. This needs their attention.

The 1SG package also includes GM's ultra-quick magnetically controlled shocks. I was impressed by these in the SRX. Those interested in a minimal amount of lean in turns and a generally more responsive feel will want them. They are not available with the V6 or without the V8's pricey 1SG package, though.

Cadillac STS Price Comparisons and Pricing

For quick, up-to-date pricing, and especially user-specified price comparisons, check out the website I created: www.truedelta.com. Why yet another vehicle pricing website? Well, I personally lacked the patience to keep using the others. They were too slow and required too much effort, especially when trying to compare prices. So I taught myself some programming and created a site where there is no need to dig through option packages, prerequisites, and the like one by one -- the TrueDelta algorithm figures these out for you in one swift pass.

I performed a few quick runs myself, comparing V8s at minimum levels of shared features. This suggests that the STS is about $6,000 less expensive than a BMW 545i or Lexus LS 430 (though the invoice price difference with the latter is only about $2,500) and about $8,500 less than a Mercedes E500. My initial impression was that the STS was priced too high. But the gap with the German cars seems about right.

Update: Oops, forgot about the elephant in the room when I first wrote this review. My father brought up the Chrysler 300C during the test drive. It's not as refined or luxurious as the STS, and doesn't offer as many features, but it has more style (at least on the outside), more power, more room, and a lower price. Make that much lower, from $15,000 to $17,000 based on TrueDelta even after giving the STS a five to six thousand dollar credit for its additional content.

Last Words

Nothing about the STS is awful, though the steering comes close for drivers seeking a sport sedan. Instead, my issues with the STS concern areas where the car is only acceptable for the class instead of being outstanding. Plenty about this car is very good, but nothing about this car is “must have.” If the average E-Class or 5-Series owner was forced into an STS they would likely not be disappointed. But I don’t see this car brining those owners on their own accord into Cadillac showrooms. Quite likely they won’t even learn the car exists.

Until Cadillac upgrades the seats and interior ambiance, I’d steer luxury sedan buyers towards the Lexus LS 430 (which doesn’t drive badly when equipped with the optional sport suspension). Until it upgrades the steering, I’d steer sport sedan buyers towards the BMW 545i.

As for people seeking big sedan style, room, and power, but who don't need all the features or top-notch refinement the above sedans offer, the obvious choice in the Chrysler 300C. The Chrysler is so much less expensive it could give all of the above headaches.

A Note on Cadillac STS Reliability

I need your help here. Actually, everyone does.

Consumer Reports' reliability ratings leave too much to inference. If one car is "average" and another is "better than average," what does this mean? Does a "better than average" car "never break?" Is a "worse than average" car in the shop "all the time?"

My website, www.truedelta.com, will provide measures of reliability that not only can easily be compared from vehicle to vehicle but that directly relate to how a car or truck's poor reliability most affects its owner. These measures will include:

1. TiSH: How many times is a vehicle likely to need repair in a given year?
2. DiSH: How many days is a vehicle likely to be in the shop in a given year?
3. Lemon-odds: What is the likelihood a vehicle will require an unusually high number of trips?
4. Cherry-odds: What is the likelihood a vehicle will require no trips?

If you'd like to know these things, then please join my panel. Your participation will make a difference. With enough people I'll be able to update reliability information monthly. With new models like this one I hope to provide an initial read within three months of their introduction. (No more waiting a year or more to see the color of a dot.) To read all the details and sign up, visit www.truedelta.com/tish.php.

My reviews of related vehicles:
Audi A6 reivew
BMW 5-Series review
Cadillac CTS review
Chrysler 300C review
Jaguar S-Type review
Lexus LS 460 review
Mercedes E-Class review
Saab 9-5 review
Volvo S80 review
Amount Paid (US$): 60000
Model and Options: V8 with sunroof