On my Tmaxx 1.5 I'm running an OS 18 with the stock pro .15 header with the hop up aluminum pipe. I've got Robinson racing metal gears in the tranny along with the foc. I also run the dynamite hybrid clutch shoes with a 72 tooth Robinson spur and a 21 tooth clutchbell. Also my underside is all aluminum with the later bars, front, rear and center skid plate along with the servo skidplate. My motor does not seem to strain with the setup and it rocks. Very nice rig and I really like the wide track. I'd like to do wider than stock but I like the stock look myself. Maybe in the off season. Robinson, MIP, golden horizons, and traxxas make some good stuff.