I compromised and knew the 4wd fannymold would be restrictive and the 2wd absolutely fine but if I was staying with a cast item (I can't afford hand build / bespoke Icconel jobbies) I guessed the next best route was what had already been tried and tested. I went for a WRC fannymold as it was proven and "off the shelf" albeit expensive it's not bespoke money. That was my logic / compromise. It also gives gain in torque too and that wins races lol.