Hey if anyone knows how to make a "test" cat converter aka... piping that can bolt up to my downpipe and my thermal full cat exhaust, IM me on AOL sn = zivicase10287 if you can make one that will bolt up to my shyt then IM me or if you know of a place to get them (doubt it) post the site here please, OR if anyone can tell me how big the opening in a stock 91 hatch si cat is.. i wanna slide a pipe through it so i defeat the cat converter but i dont' know what size pipe to get.... if anyone can help that would be great! thank you!