I've seen both the TZ-12 5 port and the Sirio EVO III run on the same track... The Sirio was in a Kyosho-RRR and it had the Sirio pipe to go with it... the TZ-12 5 port was in a Mugen with the Yokomo Mielke pipe... The TZ blew it off the track... Ok, that does sounds alittle much, but the OS was clearly the faster motor... At that point I said to myself... I've got to get me one of those... :-)... Could only locate the 3 port OS TZ-12... Bought it and since the break in... The power of the 3 port is right with the 5 port... I see more power up in the RPM range and the power seems to go on forever... Both motors are nice ie. the Sirio and OS... In my Mongoose/G4, the 3 port TZ was a rocket and I felt my motor was the faster motor on the track... And that's half the battle in any race...

RC_Alan