1. You put 21" wheels on your car? There's problem #1 IMO. AND in a multi piece?! Your car's already heavy dude... Yikes!
2. This is why if you're going to drop a humongous amount of cash on wheels, just go with what has been working since the dawn of mankind - Volk. (ok you can probably get away with BBS, Work, Forgeline, HRE, etc. as well)
3. This is why at the end of the day I'm sticking with my OEM lightweight forged one-piece concave wheels. Now I don't know what came stock on your Audi but I'm pretty damn sure they were better than those!