Coming late to this thread but I thought I'd add my two penn'orth.. :)
I just sold my (Type 85) Audi 90 quattro that I'd owned for 8 years. In it's final guise it had a TSR Pack C head and Schrick cam (a good upgrade), Boge Turbo Gas shocks (excellent) and lowered springs (a mistake!).
Even though my quattro had only the old 50/50 split quattro system there was no doubt that 4WD brings big benefits - especially on wet or iffy roads (plenty of those in the UK). It's just so easy to plant your foot and squirt off when the 2WD brigade are spinning their wheels and you can apply so much more power so much earlier in the bends that it has to be faster A to B.
BUT, having said that, there are hundreds of things that go together to make a car "handle" and hundreds of things that make it fun to drive and 4WD is not essential to that. I'm currently thinking of a Corrado because I want something that's fun to drive above all, and I still have fond memories of my (original, proper) Mini Cooper S and my Alfasud and my Mk2 Golf GTI.... All that I've read suggests that the Corrado is a good-handling, fun car!
So, 4WD will make the car put down it's power better - no doubt about it - but it might not make it "better". :lol:
PS - The Audi TT is not a quattro - it's Haldex 4Motion. We quattro snobs think it should be badged as such.. :mrgreen: