Welcome to the forums. You should check with Mike (RC Monster) about the motor mount.

Since buggies are relatively light, you really don't NEED to go with the 1515/1Y. You could also go with the lighter 1512 2.5D, which is less current hungry allowing you to run a smaller battery pack.

Good combos that would run cool would be the Quark/Neu, Compro/Neu, and Mamba Max/Lehner.

Of the controllers that run with the Neu, the Compro runs cooler, but isn't as smooth as the Quark.

You also don't need a $400+ Compro. The 16018 would be fine.

Whatever setup you go with, try to keep your max rpms under 35,000. IMO, around 30,000 is better. Believe me, you WILL get the performance.

I wouldn't say that I've twisted too many axles, but I have worn the nubs off of the dog bone end of axles. Everything gets driven harder when going with brushless. If you keep it sane, the maintenance isn't much more than it is for a nitro setup.