I am contemplating getting these. catted of course! it appears there are 3 major options. ppe 2.5" can be had for $760 (shipping cost unknown). stage 3 motorsports has some 2.5" for $766 shipped. and torrie at unleashed makes his own 3" for $799 plus $30 shipping. does the size really matter? mods now are k&n panel filter, 3 bar sensor, and a tune from torrie. in theory, my mechanic will be installing the ngk plugs and the 170* thermostat I bought from torrie weeks ago. he will issue new tune afterwards. I have no other mods planned after that.