Well I'm currently running 2002-2004 WRX wheels that are 16", 5x100 and 53 offset. Those 2004 STI wheels would be the best (same offset, and pattern) but I bet they are hard to find. After more thought, I don't like the idea of running the 2005-2007 STI wheels with adapters. I think for the money, I could just find a more expensive set that will fit better. That sucks. I also considered running VW wheels (the 18" ones from the 20th Anniversary GTI) but I've heard of issues with them fitting up right and not wobbling even though they are 5x100.
Argh. Sorry for cluttering up your thread Kiefer.