2 or 4 pole internals? I am guessing 2 poles, but would be very happy with 4!!! Given the kv is the same (although the 4600 can handle 4s now with the higher rpm limit) I am guessing the internals are updated version of the old 2 pole.
The LRP stock motor rotors have the same problem with snapping. I did get me a new rotor and haven't been able to snap it. The Orion's, LT-motors, x10, x11, x12 lrp, hacker, lehner never snapped a shaft in the same setup. I'm really liking the front bell on the new MM motors.
That setup sounds fine to me, just about perfect for a fast/fun 1/8 buggy- for racing alot of guys use 3s with that setup, but that depends on your driving style and size of the track really ( for bashing, mo speed captain! )..
As long as were talking the buggy and not the truggy, it shouldn't be a problem at all. Just make sure you have some decent batteries and it should be a lot of fun.
I've got a 4s Hyperion 6500mah and a 5s Hyperion 6500mah, would they add too much weight? I could get the MMM but would prefer the MMP for the price and it's footprint, and yes it's in the RC8 buggy :)