I wouldn't bother with a remap on the 3.2 V6, or on any Audi naturally aspirated engine.
The gains per £ are pretty small. Even with a decent exhaust, cold air intake and modified airbox, topped up with a remap, don't expect to see any more than 12hp. You may realistically see 10hp, but the car won't feel much quicker. If the map's done by a reputable tuner, it'll smoothen out flat spots, and generally make the pick-up smoother.
The only big gains would require an engine swap.
1.8T.
2.0T.
4.2 V8 40V.
4.2 V8 40VT.