The mmp is castle's 1/10 race esc. The sidewinder is more of a sport/basher esc. Sidewinder comes without a fan and can only handle 3s. Mmp has a fan and can handle up to 6s. Pretty sure the mmp has more adjustability as well and can handle all motor types. Neither of those esc's will fit in a traxxas 1/16. I know because my mmp is way too big to fit in my traxxas 1/16 rally. You might look into a smaller esc like the mamba micro pro. I also don't get why you're looking for a new combo for your merv. The stock motor is insanely fast on just 2s, and on 3s it's a rocket. Switching to a faster motor doesn't make much sense, because the drivetrain isn't meant for that kind of power. Sure it has metal gear diffs, but plastic driveshafts can only take so much.