I know a lot has been posted about exhaust systems; I'v done some searching, but haven't found much info compairing power output difference between the two. My question to members: on my '91, After a muffler swap from stock to Tiatec, I'm considering installing the '97 stock headers, as well as a full header system like SOS or Cantrell. Does there seem to be a measurable difference if test pipes are used in place of the cats? I'm not in an emmision testing State, so I don't have to retain them, but will unless they act as the final "plug" in a now free'er breathing system. I'm trying to find out if most of the header gains will be realized anyway, or if the cat's prove to be restrictive. Thanks!
