I've run the 5 port in both a 8T & a MBX5R. It has a little too much bottom for the buggy with a 13 bell I had to use 14 tooth and softer clutch spring (I went from mugen 1.1 to mugen 1.0) Then it was dialed. It's a perfect match for my 8T with the 13 bell. strong bottom and strong top to match. I would imagine the 7 port would be a better buggy motor with softer bottom and higher top end.