Having run an Optima mid briefly in the late 80's (nice selection of extras btw), it sounds like your problems are due mostly to the huge increase in power that LiPo/brushless is giving you over what the car was designed for. An insanely hot motor back then was a 10-turn, and would probably be a triple or quad-wind to tone the torque down to something manageable. Additionally, in order to make the batteries last 5+ minutes, it was necessary to let the car roll through the corners power off, then pick the throttle up gently on the exit so as not to take too much out of the cells. Ah, the joys of racing with 1700mAh cells...
