I got a D16Z6 civic and will be installing a HMT soon I was wondering if my Greddy SP cat-back exhaust would be fine with my set up, basically a DSM t25. It is 2.25" mandrel bend, or would I have to upgrade to 2.5 or 3"

 

it'll work fine, its not like you're gonna make 400hp with that t25 anyways

 

that should do fine, i picked up 18 hp when i went from stock to 2.5 mandrel with no res. or cat, just straight pipe.

 

i have the sp as well. im gonna use it until i decide to step up to a true 2.5" turboback, or 3" if i can afford to. i feel even 2.5" is a significant upgrade because the sp begins at about 48mm to match up to the stock cat. it only begins to flare to 58mm somewhere along the middle of the b-pipe.

 

I have the greddy sp, it's 2 1/4",with the t25 turbo on a d16z6, and it is soooooo quiet, you can barely even hear it!