You can port the factory exhaust manifolds yourself, but not the crosspipe and uppipe. otherwise, grimspeed makes their own and sells ported exhaust manifolds. Same as wrx exhaust manifolds,.Their flange and tubing size is what makes their stuff top quality, gaskets aren't too bad either. I would do the downpipe first, and please don't do straight pipe. it only sounds cool if your actually in a race car, I did straight 3" to a magnaflow muffler and it's loud when I want it to be.
Last edited by USLiberty; Yesterday at 11:32 AM..