Thanks for all the replies guys, I did find a few but now I'm not sure...
The muffertech.com is just like the carsound with the flanges for $110 I believe, and the landspeedracing.com is supposedly the powercore high flow cat? Is it really worth the $250? I'm not trying to throw cheap parts on the R but the extent of my modding is going to be the JDM DC Sports 4-1 header (All ready have) high flow cat, cat back exhaust and that's about it, maybe some other minor accessories but certainly nothing major. Any thoughts or suggestions on which one? Thanks for the help again.

-Jeremy