The spiral gears are a must I think, better then straight cut. I would also upgrade the front and back upper bulk head to aluminum. I found the plastic actually melt with all that power. Amazon sells a pair of no name for under $100. I have GPM. They will also hold on in the diff covers better since 2 or the 5 screws are gettin screwed into metal and won’t back out.
Try the PNW belt drive, It is amazing! It seems much easier on the drive train & I think it will also save the motor shaft from snapping in most cases.
