the st-15 would be great i bought just to get use to nitro rc. now i cant get away from it curently i am extending the chasis and installing a trx 2.5 with a n4-tec rear end gonna buil a custom roll bar buy some extended a arms and a few other goodies im hoping to make this thing break 60 with the 4-tec rear and the trx 2.5 if that doesnt work ill see if the new trx3.3 gets more revs if it does ill consider installing it im gonna make this thing blow them out of the water