Why not just buy a bolt on option? They are so cheap these days and fit strait on. Or even a second hand exhaust will be fine, I got myself a ss catback ganadore exhaust in perfect condition for $250 off ebay!! They are worth a hell of alot more then that!
Have a look in the Classifieds section for something in your price range. As for fitment, do it yourself and learn about your car.
If you cannot find some thing you like, ask some members for some sites that stock R33 bolt-ons.