I just re-read the Neu specs and it seems that the 1512 2d and the 1515 1Y have similar specs. Same resistance rating, and about the same current draw at 10v. The 1515 is just a tad longer and heavier. I suppose that going with the motor with more torque would make sense since I would have broader gearing options. I just hope that it wouldn't be undergeared when on the track.