I have the GTM 3 inch. More back pressure should help for sure, and I think the restrictors are the way to go, they don't have the same potential of failing or melting like the HFC's. Would be cool to have a modular section of exhaust that you can take out and change the amount of restriction (different baffles / perforated stainless disks etc..) so you can get it dialed in perfectly. - Hope it all works out.