Thanks JustPoet and YouWish. I haven't found any binding or extra friction in the drive train, so maybe I'm just expecting too much out of this motor. I'll take the punch down a bit and go back to a 17 and see what happens.

I was at our local track yesterday (which shouldn't even be possible in December!) and was practicing with a few other truggies (a Losi, Durango and Associated). My Tekno was killing them on the turns and jumps, but they were absolutely eating my lunch on the straight until I went to the 18 pinion. I didn't ask them about their gearing 'cause it would have been apples and oranges. Who knows. Maybe they were running stupid-hot too.