[jhautz]

I have both the 1515/2.5D/F and the 1512/3D/S Both are great 5s motors for a buggy. It really depends what the primary use will be. If you will be bashing it and driving it around in grass and such go with the 1515. If you are building a dedicated track vehicle go with the 1512. The 1515 is a bit more versitale with the gearing it will allow you to run due to it larger size and more power, but the 1512 is ligheter and more than enough power for any track.