I too am very cautious about using adapter plates for brake calipers. Invariabley the adapter plate (no matter how thick) will flex under heavy braking. This combined with the heat expansion can cause an inconsistent brake pedal.
Engineers hate them too as you are replacing two fixing points with four. No matter how much thread locking compound or lock-wire you use, there is still a risk.
The VL rear diff sounds interesting though..any thoughts anyone?