A friend of mine just bought a 96' GS-T to replace his 90' TSI AWD. He's been going all out buying stuff from Buschur for it and he plans on buying the Tsudo exhaust from ebay to replace his stock exhaust. When he does so he's going to give me the stock exhaust. From what i've heard from a lot of people on DSMtalk.com the GS-T cat-back will fit on a N/T no problem. I just want to double check and make sure it will fit. Also, does anyone happen to know what the pipe size is of the GS-T exhaust? I may just use the piping since it's said to be bigger and get an N1 knockoff muffler instead of using the stock GS-T muffler.

"Things we've seen before" is an excellent forum that contains more knowledge than you would ever want to know. You don't even have to go through all the trouble of posting and waiting for an answer!

http://forums.2gnt.com/dcboard.php?az=show_topic&forum=23&topic_id=73&mesg_id=73&listing_type=search

Short answer: Swap your RS/GS single tip muffler for the GS-T muffler and leave the rest of the piping alone.