Original Plan A was a new AC motor (Hyper9) with Tesla batteries, but after running the numbers the cost was going to get crazy. Probably $20k when all said and done, and certainly could not justify that much into an old bug.
So Plan B is to go cheap. I'm actually really excited about this plan. Per all my research these old big, fat, heavy tow motor DC motors are beasts that can be over sped and worked hard, and they last forever. Couple with a used controller, used Leaf batteries (maybe not the best performance, but great pricing), and anything else I can find on Ebay or the like should save good money, and get great performance. Quick back of the envelop calcs looks like I can go this route for under $10k
Performance with Plan B should be as good if not better than A. With the big DC motor, and the money saved, I can get bigger controllers, fatter wire, and overall plan on a beefier system. Quick calcs -- if I can pump out 500A out of a 1000A controller @ 144V I'm looking at almost 100HP. Not sure if the batteries can pull this off, but the system will be capable, and batteries could be upgraded in the future.