I too had one of the modeltech systems. I had the 12s and ran it on 12 cells. I had a very light E-Maxx and the controller thermalled after 5 minutes and once I put a fan on the controller, The runtime was still only 10 minutes or so on matched GP3300's. I would estimate that the motor reached temperatures of 160 or higher and I had to cool down between runs. (not very fun IMO)

Like Metal Man, I think that you should try to sell that motor on ebay and then get a more suitable motor (8XL).