The MMP is too small for the buggy.
But serieus for just a sec: if you want to run sensored motors go with the MMP. It's can handle the 1/8 buggy and your 1/10 trucks just fine, plus it's cheaper than the MMM. Only downside is that you can't (or atleast it's not really recommended) to run it in 1/8 trucks.
My bet would be on the MMP because you want to drive sensored.