I think you'll want the better mount points and endlinks with that beefier bar. It is my understanding they are crappy on the 02-03 WRX models. You probably know this already.
04 rear mounts is supposed to be better than the 02/03. So running a 20mm will be no problem. Chet, I'm currently shopping for a cobb front/rear with mounts, but will not pay retail or close to it. sorry, that's just stupid in my book. If a guy backs out on the set-up on nasioc I'll jump on that set-up. However, i still want the 20mm for sarah's wrx. endlinks- i have those covered
Whiteline. Shoot me a PM if you want the info from the NASIOC vendor I got my stuff from. I bet you could get a decent size FSB for ~$100.