I would see if you could sell the 3.5" piping and buy 4" piping. If you want to know of some good places to get materials let me know. Too bad he didnt get to use it on his SR20. I sold a friend a GT2871R for his SR20. It's fun Your stock sleeves must be non-existant at 84.5mm I have a Fluidampr. One of the wisest investments I made IMO. A month two months. All the same in a way. Take your time and dont skip over anything. Good luck