for the thread, I turned down a motor change this season to stick with my os .12 CV-R :O any other motor like a Fantom or a Sirio will need to a carb restrictor anyway! I do love my CV-R
as for the .15 CVR, it has been discontiunued from tower! dont ask me why, and i dont see a replacement for it either. but stay CLEAR of the .15 CV, make sure its the CV-R. the .15 CV has less power than the .12 CV-R.
and remember, if you gear the truck low enough to pop wheelies, its geared low enough to detonate your tranny gears