Fitted it into the b44, 14T pinion and 6000 mah lipo.

It's certainly quick (stupid fast), you are right about the speed, it's not really drivable at full throttle, however if you can control yourself the straight line speed does feel good, just need the right (very big) track and some careful corner planning.

So far no issues with over heating.

Long term I think though I'll move the MM7700 into a road car!!

Cheers
Mark