Generally engine's with more ports have more top end power. This is not alway's the case but usually 3-5 ports have more bottom end than a 7 or 8 port. The Go 5 port has the most bottom end of their engines and maybe could be hard to drive for a novice in a buggy. The 3 port race spec is just a very smooth easy to drive motor but it is very fast also if that makes sense. The 7 port has more top end power for faster longer tracks.
Rex