Yeah, I don't really know.. It's not a buggy though - it has a 2-speed, which in theory anyway maybe obviates the need for torque you would need in a 3-diff car??..
A Werks B6 with 2058 would be an alternative, or the Alpha A872.. With those I could at least run them in a buggy down the line.. They both work out to be a tad cheaper too..(The RB combo is at amain for about $305 or so with the discount, the B6 with 2058 at Tower for about $250 or so.. 'Bout the same price as the Alpha locally..)
I was just at the local track yesterday, with my DM-1 and Go GXR 5-port, and it was fading down the straight.. Great engine, but this straight is lllllooooooonnngggg... I'm actually not clear as to what I need more in this case - more gearing is clear, but will the muscle of more displacement bring the speed, or the higher revs of a smaller 21? The Go 5-port has plenty of torque IMO - in pretty much all areas..