It may be a while before I can afford or make any changes, but yes the point of making the battery rack modular was so I could replace it without any reworking of the frame.
I would however (if possible) like to find a 60 VDC brushed motor rated between 1kw and 2kw.
I was pleased with the performance of the 60 volt setup, but it was hampered by the poor build quality of the motor. It's frustrating that there are so few usable motors for this kind of application. So I'll keep my eye out for good deals on golf cart motors.
Meanwhile, it likes mud.