I just picked up my new 2006 A4 a couple of weeks ago with most of the conveniences offered (except the navigation system and the ski sack).
I drove the two previous A4 models (2001 and 2003), so my review will concentrate mainly on the differences.
The engine is more powerful and the few extra horses and torque are great. The car can now coast up moderate hills without going into any significant RPM it just feels much better. It also takes off much faster from the standing position. I would even say too fast its somewhat uneven compared with other cars of similar power.
The other change to the engine (well, its a different engine altogether, but the other difference) is DFI (Direct Fuel Injection). I dont know if this is the culprit, but the car sounds a bit like a diesel when accelerating (no, dont worry, no clicking sound at idle), and it feels like it doesnt have the same engine breaking resistance as the previous engine (who knows maybe the updated gear box has something to do with it).
The 6-speed tiptronic is definitely better no more jerky switching to the 1st gear when coming to a stop. Gears seam to switch quickly and together with more power it allows the car to stay at lower RPM if you choose to drive economically. The computer now also displays the current gear number even in the automatic mode. This is a good feature especially if you are like me and enjoy switching between the auto and tiptronic modes. The computer displays the gear, which the car intends to have. That means the display is slightly ahead of actually changing the gear and I found it helps me prevent switching to tiptronic and doubling a gear change with the computer (if you lost me then just enjoy the gimmick J).
I do not understand why the engineers at Audi cannot figure out a hand break position, which would not lift the armrest. If you like the armrest in the lowest position, you have to put it there every time after using the hand break. That step was also just made even more difficult as the armrest must be lifted before it can be lowered bad idea.
On a positive note, and I like it very much, is the automatic seats and side mirrors with memory, which are even linked to the key with which you open the car (you have to program that in a new car before it works, so read the manual). The power seats option wasnt available on the smaller engine before (at least not in Canada) and 2 thumbs up for Audi from all of us who share the car. The drivers seat also comes down a bit lower than the previous model, although not as (nice and) low as the 2001 A4.
Thank you to Audi again for giving the smaller engine A4 the auto dimming mirrors back taking it away with the 2003 model was a low blow J. The side mirrors also have electric folding feature and the right mirror will lower to a parallel parking position if the mirror knob and the gear are both in R positions. The rear view mirror has a compass one with a see-through display rather than a hole that was visible on the 3.0 older model.
The car is now equipped with an adaptive power steering (cant recall the Audi term for it). It makes the steering much easier (lighter) at lower or no speed. The car resists steering more at higher speeds. I thought I would really like this feature, but I definitely do not. The steering in the previous models was just great and they should have left it alone. The steering is now generally softer and much, much softer at city speeds. That amplifies the car drifting to either side with the road angle. When you turn, depending on the speed and how sharp you turn the steering system often delivers unexpected resistance. I am not saying it is wrong and maybe with time it will grow on me, but for now it is a bit of a pain. My suggestion is to test drive the car before you buy (common sense, right?).
Rain sensing wiper system, automatic lights, short and long beam xenon lights, color computer display, customizable computer options are all very nice features, which will add to your smile. The wiper system works very well and I cant get enough of it. They also removed the lamp washers from the package, so you no longer have to waste the windshield washing fluid on the lamps for once removing something was a good thing (the other way was to keep turning off the lights before washing the windshield J). If you liked the washers, they are still available as an individual option.
The steering wheel has changed the shape and looks. Whether one likes it or not is a personal thing, but the fact is that now it is further for the hand to activate the horn. With the old wheel you could do it quickly with your thumb. Now you have to move your hand, which is not good in an emergency situation bad idea Audi.
The other, neat feature is the headlamps that turn as you turn. Do not expect anything dramatic, but it does help in dark conditions and its ever so cool! The feature has a minimum speed, but if you were ever impressing your friends with the xenon lights going up and down as you turned on the car, now they go up and down and left and right cant beat that J.
Here comes my biggest problem though. The 1st Audi I picked up (2001 model) had to have the locking system fixed within a week. The 2nd had a knocking problem right of the lot, which resulted in the replacement of some of the steering system components. This new car, right of the lot, was significantly misaligned (pulling to the right) and had a knocking problem too (although it was caused by some lose nuts and bolts go figure). So I had to drive the car for a week like that before the service had a spot to fix my brand new car and on top of that they put me in a rental Nissan Sentra (bad PR in my world). Maybe, I am unlucky, but based on that I will be test-driving the very car, which is being sold to me before I sign for delivery from now on.
Ok, so there are some good things and some bad. I am still bitter about the car not working properly upon delivery, but once I get over it I think I will enjoy the car over its predecessor in spite of the weird steering and jumpy accelerator. There is an array of new features, some of which I really ached for, to keep my spirits up.
If you are driving the 2001 line of A4s, and you resisted upgrading to the 2003 line which was a good decision unless you really, really needed the extra space in the back, you can probably now go ahead with the upgrade. I would rank the 2006 better than 2001 and leave the 2003 behind both of them. I would also recommend test-driving the yet to be released 2006 BMW 325xi before making a final decision. I drove the non-all-wheel drive version and I really liked it. Unfortunately the xi wasnt available yet.
I didnt comment on a number of other important features like suspension, cornering, breaking, fuel economy and a few other things. I consider them either the same or somewhat better they didnt stand out so far in the driving conditions experienced over the last couple of weeks. You will also find more information like this in the more official reviews. I concentrated here more on the experience that I didnt necessarily anticipate having read the other reviews and I hope that this will complement the rest of the data out there.