Forrestboy if you are talking stock and you are on small to med tracks 3 port for buggy and 5 port for truggy. Big flowing tracks 7 port for buggy and the .25 6 port race for truggy. That .25 is just a monster and truly is the best of both worlds, good runtime and monster power. Modded mills you can get which ever you want I have seen modded .21 3 ports in truggy screaming. The 1 thing with a Go mill, is you will never be hurting for power. Just find the clutch that it likes and your golden. Modded I like the 5 port and so far am loving my 3. to be honest I have never even seen a modded 7 port because its just an awesome performer in stock form. My buddy last year I talked him into getting the .25 modded for a Hyper st which is super heavy and that thing blew tires off and still got 8:30 mins with an 086.