grab a stainless tubing kit from vrs. get a magna flow muffler from any where and then get the longest resonator that you can fit on there.
2.25 inch would be a good size and you will keep more of the low end power. but if you plan on going turbo (smaller turbo like a t25) then get a 2.5 inch.......if you plan on going balls to the wall turbo (t3/t04) then wait and get a 3incher.
p.s. go to
www.se-r.net and read up. also this needs to be moved to sr20.