With our solution you can do either NO rotor cooling (like the Rev U Tesla LDU), or as an option oil cooling can be added on. Our manifolds will be backwards compatible, so if you put it on without cooling and you change your mind, the cooling can be added on later (the drive unit would need to be removed from the vehicle to do so of course).
The cost of the base version (rotor cooling delete) will be $599 for the part, either available for DIY, or we can install it here at our shop. The labor should be somewhere in the ~4-5hr range to install it (drive unit needs to be removed from the vehicle to install). We still need to do some more validation and finalize parts sourcing for the optional oil cooling parts, but that will probably be in the ~$500 range, plus of course the extra labor to install. We would of course recommend a drain setup if utilizing the oil cooling for the rotor.
There is of course a risk of ATF leakage if there is a seal issue on the oil cooled option, but with oil there should be some significant advantages:
1. Lubricating properties of the oil "should" keep the seal from wearing out as quickly.
2. Oil is non-conductive, and non-corrosive, so IF it does leak, it shouldn't "destroy" the drive unit like coolant does.
As far as disadvantages to not having cooling, it's hard to say for sure without long term data. Clearly Tesla has decided that will be their path forward, and one would like to think that they did some sort of serious validation to make this sort of change, but who knows... If I were to guess, the most likely downside would be a decreased lifespan of the rotor bearings, but I think that's a worthy tradeoff if it means the rest of the motor doesn't get destroyed by coolant intrusion. And honestly, the amount of cooling the rotor does get in the stock configuration is teeny tiny, as the main restriction is a ~1/8" hole where that circuit passes through the two case halves. As it is already, the rotor gets hot enough to discolor the steel laminations.