I have the HKS exhaust and its 2.25" to a 2.5-2.75 (i think canister to tip)! It's loud but most HKS exhausts are loud.. I'm going to the exhaust shop tomorrow to get an estimate for a midpipe because I don't want to spend $350-$500 on a cat-back ie racing beat, skunk2, jic, etc. Hopefully it'll only cost me around $50 mandrel bent! Nice angle like N1 check it out http://www.geocities.com/protejay5/protege5.html
Ohh I guess you can have a shop hack the axle back of the hks and weld on a 2.5 from the cat.. I'll ask the guy!
unless your boosted, 2.25 is more than adequate. 2.5 is usually reserved for turbo apps. we don't have enough power to be pushing exhaust gases out of a 2.5 inch pipe.
