1st, I dont beleive the audi a3 3.2 would have different brake caliper than the 2.0 turbo
2rd, Audi a3 offset is 55, audi a4 is 45. That mean the a4 wheel on the a3 will stick out of 10mm, putting your tires closer to the fender, many consider 10mm acceptable.
3rd, I'm running a winter mags setup on my 2.0 a3 2006, 205/55 r16. 5x112 bolt pattern, 55 offset and there is no problem, half a inch clearance around caliper

The best way is to test mount the wheel and dont go over a offset differance of 10mm.

Tire rack people are really good an reliable.