i have a random backfire every now and then, dunno why. on power, so i was thinkin about a Rotax swap but now after seein the $6K number im like f*** that noise. i have a fully rebuilt motor with a Namura piston. i want more power to get up and move but i dont want to lose any reliability. what all do i need? id like to see 65mph and not be killing the motor while doin it. i can hit 58 now but it sounds like it gonna explode. id like to gain full range power. slow, some mid and get a bit high. i can get a DG exhaust if i trade my stock one.