go with SLP. i just called them and they couldn't have been more helpful, they gave me the exact clutching and jetting for their pipes.
2006 600 HO RMK 144 w/ SLP pipe and can, SLP powder pros, SLP clutch kit, SLP air horn conversion kit, 3" powermadd riser, skid plate, and snow scratchers.
2002 indy 500 stock