Originally Posted by xluben
While I had them off, I measured the stock vs. SPT midpipe. Stock is 2 1/4" and SPT is 2 1/2". SPT has the midpipe go straight into the muffler. Saves about a foot of piping and a 90 degree and a 180 degree bend. I'm assuming this would all add up to slightly better flow, but probably doesn't make that much of a difference (since cat back's don't really seem to matter).
Isn't the 2008+ hatch SPT exhaust supposed to be 3"? It does taper to 2.5" at the down pipe connection, but it's supposed to be 3" all the way back. When I had the SPT exhaust I measured it in a few places and got 3" (aside from the down pipe flange). What section of the mid pipe did you measure?
Is there a different exhaust and part # for the 2008+ hatch WRX SPT vs STI SPT?