Mugen MBX4-XR Conversion?

[SilveradoHD]

I have an old Mugen MBX4-XR and another parts buggy in need of a powerplant. I am looking to convert it to brushless. I was wondering if the RC Monster motor mount for mugen will fit in the MBX4XR series of buggies. I am not sure if the diff mount is the same as the MBX5. I already have a v2 MMM that I run in my drag rustler that I could use in the buggy. I plan to do this on a budget and use the cheap zippy packs. Would a 4, 5 or 6s battery be better to use on a Medusa 2000kv? Which pinion should I get for bashing? I will mostly be bashing this car as this old Mugen is built like a tank, but would also like to drag race it. Would the Medusa 2000kv motor be sufficient to move around an 8th scale buggy?