can a 2dr catback fit on an 08 si or where can i buy one

 

your question is a little vague...

A 2 door catback will fit on an 08 si coupe.

you can get a custom exhause made at an exhause shop or try looking around on http://corsportusa.com/store/catalog/

I know you are new so read the stickies at the top of the forum page.

 

im not new. im just curious.

 

you are new in the sense that you only have 3 posts and ur avatar is a giant sign that says NOOB. But anyway, the 06 07 and 08 civics are exactly the same with the exception of a few minor things like vsa, shift boot, tpms, etc. So anything designed for an 06 will fit the two later years as well.
And if you have a sedan, but want a coupe exhaust, all you need is a 2 inch extension