My buddy has a B6 1.8T 5speed A4 (non Quattro). It's a nice car, but it's a total pig in the performance department.

My old '92 Acura Legend (CAI, catback exhaust, engine damper, few other little things) pulled pretty hard on it, and to me, that car was pretty slow.

If you want a quick car without putting a good bit of money into, it's not for you.