http://forums.m3cutters.co.uk/index.php
My user name there is Steve Sarg - apologies for providing links to a non-Audi forum, trust this is okay in this case?
The main issue is cracks appearing in the rear subframe - BMW will repair these FOC up to 10 years old, but either way, you should definitely have this checked out before committing to purchase, better still is to find one that's already had the floor repaired and reinforced.
http://forums.m3cutters.co.uk/showthread.php?t=28569
There are always plenty of cars for sale on the forum, and
most of these are well looked after. I'd definitely recommend looking first at the owner's cars that have good project threads on them, more detailed than a service history in most cases. Right now there are 5 Verts up for sale between 9-10k although they're all a bit older, 2002-03.
Most will have 19" wheels, but again, there are always plenty of wheels up for sale, swapping to 18"s you can probably even make a profit along the way.
Plenty of indy specialists out there, so no problems finding somebody good to look after it.
Finally, don't expect a forum anything like this one - whilst there is plenty of good quality technical info around, there are also a lot of argumentative kno8heads, don't say I didn't warn you!