NEED? No. Want? Yes. If you plan on doing conversions or kits they really are some of the best types of gearboxes as they are very low profile which helps with clearance issues. They are also steel 3:1 which we have not had yet. We do have the steel 4:1s already, but the 3:1 will be nice. It will mainly be for the KV1 and Panzer tanks as they already have 3:1 stock, so these will not change the speed of the tank, just the reliability of the gearboxes.
The black motors are about the same as as the previous motors, just black. They should run a bit cooler as well. Never hurts to put a heatsink on them anyways, they are cheap for that size. All of our new motors will be this color. I will most likely have the gearboxes changed to black as well, it really looks good