electric revo questions

Is the MM esc is a capable unit to power a heavy truck like the revo, or should i think to buy something better?,, I've take a look on the MGM controller but it's alot of $$$ for a controller.

You say that if i keep the two speed, gear it 16/40 and if i lock into secont, 12-14/40 did the job?

I've a 13, mod1 here, and a 18, so the 13 for the lock option and the 18 for the two speed option??

But i think that i'll order a 9XL right now. But on 4cells, is i'am better with the 7XL?

Excuse me Brian, i know i ask alot of question, but before to start a big $$$ conversion, i want to be certain of what i did...!