Hey Rich, you are right to a point. I think alot depends on the track you are running on. If you run on a track with a lot of longer straights, then you would want a larger spur cuz you can pull longer going down the straight before your motor tops out and the performance curve flattens. If you run on a medium track with medium straights or a smaller track, the smaller spur will be better because you can get to top speed quicker. I have always been told you want your car to be pulling(accelerating) at least 3/4 of the length of the longest straight on your track. Just my $0.02
Torq