Have you seen the stock downpipe? There's no such thing as free flowing with the stock exhaust, or at least stock dp, on the car. The turbo is a K03 I believe, so a realistic upgrade would be to just buy a K04 instead of wasting time trying to get a new wheel to fit.
Completely stock with my uncle's tune it puts down 253whp and 323wtq at 2400 rpms, but falls off around 5-6k. The stock turbo sucks, so from a performance standpoint, the intake, exhaust, and turbo need to be upgraded.