You have come to the right place my brother. I have a 94 TT MK4 myself. There are way too many options to choose from. I personally went with a Tanabe Medallion because it produced a quiet sound note while idling but sounded fairly aggressive under throttle. All exhausts will produce the same number of hp. It comes down to what aesthetically looks right to you and sounds good. Check out a few of the Supra forums for sound. They are also great for technical information.
www.supraforums.com
http://www.toyota-supra.info/forums/