Inferno
GT (dont make me have to guess what the smegg you're talking about) is a 1:8 scale TC, would make for a fast vehicle me thinks.
I dunno if Mike sells a suitable motor mount, but if you can find or make one, theres no reason why the MMM combos wouldnt work. Single speed would be fine as BL motors generate vastly more torque than nitro engines, though it depends if you want reverse or not (bashing purposes). With the single speed I would say the 2200kv motor would be best, or with the 2speed the 2650kv motor would be better I reckon.
I would say have a look around at similar builds and conversions to gather more info and ideas, as Im all out of 'em...