The ST *is* a "bargain pattern motor", but not for 2M, 5kg models. Just won't spin the props needed. When I was using the ST on Hanson EMC2's, I was putting 27% nitro in it, and still turned 17 x 10N's as a "max"....If you can turn rpm's, noise notwithstanding, then it can do the job.

The newest ST carbs have all the fixes that came about from all the learning in '97-98....info/history on my website.

The best ones now are running with the Perry pump, the VP-30, and a good pipe....but you still need to keep the r's up to stay in the torque band of the motor. It's more rpm than torque by design, I think.