Also I was thinking about your motor, if you read the DC motor thread about advancing the timing you can get some better rpm speed from the motor and I am sure you can use more amps also because you do not use full throttle for long periods normally.
What settings are you running in the Kelly controller? A Soliton jr would be very effective with that motor I believe when you advance the timing a bit and optimise the motor a bit more for automotive use. Lots of opportunity for good performance and not spending lots of money. Soliton will take 6 Tesla modules also if you like and can set motor voltage separately to protect the lower voltage of your motor or upgrade later.
Good luck.
Cheers
Tyler