well boss, in my mind, there ain't nothing touching a TRT 2Fast 80 kit for the minerelli. here in bermuda, I race a benelli 491 with an untuned 2fast minerelli motor, using MHR over range system, MHR inner rotor, kevlar belt, delta clutch, MHR transmission casing and secondaries, MK manifold and 28 OKO carb. the raw low end torque increase I got over a 70cc motor was quite noticeable.
like everyone has said though, the problem has always been the pipe. i originally thought a bigger kit would need a bigger pipe, so i went with a yasuni C30. after alot of testing with different weights and clutch shoe settings, I got my bike to perform pretty well, puttin out roughly 25-26 HP. THEN I put an MK PR3 pipe on the bike. WOW! The torque went through the roof and it enabled me to run heavier clutch weights giving the bike way more drive and gave me another 4 MPH top speed.
The bottom line is, with quad racing, it's all about the torque, so if I were you, I'd go with the 2Fast by TRT.