i think the first thing to do to try and get a couple of more rpm spool up is put a cyclone and see what it does cause what i think the 280s 35r is fine for the street but sheetmetal intakes lag a little then if that works try a stock exaust manifold with an adaptor platesee if you can get a little bit more with that you can probly get 500 to 1000 rpms but i think you set up is solid