I've just bought a Jan 05 (54) 1.8T cabriolet (heated seats & bose sound system). Prior to this car, I had a BMW 325 Ci Sport convertible on a 02 plate. Performance wise, the BMW wins. Despite it being a 2.5 litre with the added weight of a convertible, it still felt very lively and the noise the 6 pot made was to die for. Comfort wise, the A4 wins. The A4 is a better place to be. My original plan was to buy the 6 pot as it was cheaper to insure than the 1.8T (I'm 22), anyone who has owned a 6pot before will know how smooth and what a lovely sound it makes and also, I wouldn't have to deal with 'boost' issues as many turbo cars have. e.g. boost leaks, split pipes, being underpowered etc.
So why didn't I buy the 6 pot?
I've done a little research, as well as consulting with a few VW specialists around here. The 6 pots in the A4 range are not 'that'
reliable as others. They suffer from cylinder head cracks and more commonly, headgasket failures. If you also look on the Autrotrader, eBay and gumtree, you will also see the V6 cabs are waay cheaper than the 1.8T models which for me is a big downside as I usually get bored of my car within 6months, so I don't really want to see a big depreciation.
I live in Leicestershire and I travelled to Southampton for my A4. I drove back that day sitting on the motorway at 70 with the heated seats on. I really haven't had a journey that comfort in such a long time. The seats, the feel from the steering and just sitting in the car, overall it was the best thing. Infact, I did almost 500 miles that day as I also volunteered to drop my little brother off to uni in Bolton. It is a great motorway cruiser with no steering vibrations or any irritating noises.
City driving is great also. The turbo spool sounds nice, the feel from the gear changes feel effortless. By any means, it is no gran tourer, however it handles like my Golf GTi MK4. When you're driving the car, you feel relaxed and because I have the sport version, the seats are very comfortable and hug you in place. What ever you do, make sure you buy a sport version as the seats in the SE are flat and may cause back pain (in my opinion).
I bought mine with 5 months of warranty remaining from 'VGS automobile'. I have the 5 star cover which is great but I hope I never need to use it!
Overall, I would give it a 10.
Here's a little list of things to check for which I made before I went to view mine
1)Roof storage box (many have broken ones)
2)Glovebox hinge (mine has been repaired by previous owner)
3)Hood operation
4)Rear window (check stitching around the rear window to hood)
5)Rear window demister (check to see it works properly and not half window)
6)1.8T only ( remove oil cap and check if you can see any sludge)
7)Check if radio works (antenna wiring usually breaks)
8)Check for any oil leaks (near alternator area if greasy, rear if you can (half moon gasket)
9)Thermostat (should warm up within 5miles of continous driving or 10 mins. Temp should not drop down when moving)
10)Quattro only (check traction light illuminates by pressing the ESP button. Should not hear a grinding noise from rear at slow manoeuvre)
11)Check in fuse box area for red emergency key as it used for closing and resetting roof
Lastly, for my own piece of mind, I went into TPS the next day and changed the oil. If the particular vehicle you are looking at has been on a long life service, I'd inspect the oil pickup and either clean or replace. I'm using the PLATINUM 5w40 for TPS and will be changing it either every 3k or 5k. This part is only important if you buy a 1.8T variant.
Kind regards