3 motors, 2 cars, and two esc........

[lincpimp]

I would put the 1515 2.5 in the emaxx, and the 3d in the buggy and gear it up. The buggy will not mind the taller gearing as the tires are smaller and the overall weight is lower.

Both systems should run cool. You could put the medusa 60mm in the buggy and gear it down to reasonable speeds on 5s. Not sure if that will run as cool as the 3d. The 1515 2.5 is a good 5-6s motor and will move the emaxx well.