I run the 3 acing gear diff with the kit oil and it's way to thick for rear wheel drive. Even using 30wt shock oil it is too tight I think. I made the car really push as there was no rotation from the rear. Gone back to kit diff and it's perfect.
To be fair I have found a loose kit diff works well for a tight indoor track. 3 racing diff will be good for the m05 but can't get the thing free enough for the m06.