RE: 4WD FG MT?
Belt is a lot quieter and the problem with shaft drive is that the chassis would have to be very strong or re-enforced. If the chassis has any flex it could bend the shaft or strip some gears. I think with the belt version you can still have the belt slip a bit since a full 4wd is not always needed. They may be using a one way bearing in the front too!!
I know how everyone is waiting for it and I'm sure it will be sold out before we know it!!!