Ok i have the GM Performance exhasut. what downpipes are you guys using with this exhaust. the reason im asking isnt the exhaust 2.25 in. my question is does the downpipe have to be 2.25 in or does it matter.

 

It's actually called a b-pipe, not a downpipe.

You could buy a header that comes with the b-pipe with it (example: 4-2-1 Header Design).

As far as the diameter, if you find something larger, that would still be fine but you would probably need someone to professionally weld it.

 

Go to www.zzperformance.com That is the downpipe that I bought and works fine, but I did get a custom 2.5 in cat-back. It will bolt right up to your car though.

 

but i have a 2.25 catback so that wont work will it

 

the size of the pipe really doesnt matter, depends on the flang, and what it will bolt up to. i know the CA dp will work on the stock exhaust flang.

 

You can make it work even with the diameter difference.

 

It will bolt right up.