Novak Brushless Conversion

Bushy,
I have the Novak 4.5 in my MP777 and take it to a nitro track. Last night at practice the nitro guys were impressed with it and the buggy was doing a backflip over a jump (mostly due to my poor driving skills).
Make sure to use both fans just to keep temperatures down, honestly the system (unless it is defective) is pretty solid with the 5mm rotor. I was running on an off for an hour yesterday and the motor/esc never got very hot (I did thermal the motor one day when running 30minutes constant in grass).
If you haven't purchased the motor yet I would suggest going with the 5.5 or smaller, my 4.5 has way to much power from a stand still, The nitro track out here is quite large, but unless it is good and wet I cannot give it full throttle most of the time (to much power). I honestly think if I was running the 5.5 or 6.5 I could probably get better lap times just because the wheels would be getting better grip.
In terms of speed my buggy was going 45mpg on the street with bald tires (no grip, sliding all over the place). With some good on-road tires/foams I would probably have been doing 50+ (that is on a 4S setup w/ a 10T pinion).
But honestly, that kind of speed at the track is not needed (anything over 40mph is overkill IMO).