I ran Brocks sidewinder on my stock motor 02 busa with PC3r, box mod, pair blocked off, ect. and it hurt my performance even after a dyno tune so I went back with Brocks Gen3 streetsmart pipe and his map and the bike picked right back up. I would say you need atleast higher compression pistons and cams for a sidewinder or a 1397.
same mods as above , i run a muzzy without the fiberglass baffle. metal baffle still intact, have to have some back pressure.stock motor as well.dynoed at 165 hp in the middle of june 98 degress outside with a ton of humidty.told i will gain at least 10 more ponies when it is cool outside. who knows, but am very pleased with mine