Oops! Type O. Sorry. I meant to say, the OS 18 CV-RX is the best and very powerfull drop in replacement for the MT2, but, I wanted to try a different engine, something new. Has anyone else tried to drop in a NX15 in their fun factor. What issues did you find, or how much power did you find it has when compared to the OS 18 or other engine options. Thanks again to all, keep the comments coming.