I can't speak the gearing for that particular car, just run the same gearing you are now, and then change according to your needs. Pinion/spur gears are cheap. Go brushless, I wouldn't convert any vehicle to a brushed system, would be a waste of time.
ARCTIC DOG RACING (Nitro free since 2009)
"Straights are for fast cars, curves are for fast drivers...."
8ight-E / 8ight-TE / T4 / Slash