According to the guys at Power Engineering, the front and rear rollers are independant. With my car on the rollers, the rear wheels are visibly turning much faster than the front.
Apparently its fine on the road where everything turns at roughly the same speed.
The difference between the axle speeds on the RR would fook it up completely.

Gearboxman - Interested in the £175 +v VC. Do you fit?

Anyone know how many labour hours I am looking at for fitting??