It's a tough one, the SRT4 is the faster car hands down, and will respond to mods a lot better, on the other hand it's a 4 door with a neon body and interior. The SS seems to have a nice interior and body, but I don't see them hitting 12's without too much work. As far as the ACR model, really not worth it, just buy an 04 SRT4 now, get the moar suspension and you've got the same car for cheaper(considering you buy a new 04).