I've noticed a few things about the M-05 so far. First, a lot of the tuning logic that one learns on the M-03 doesn't apply. Try M-03 tricks, and your car will be a pig.
I tried the David Jun trick with the ball diff. I don't know if I did it wrong, but it sounded like a garbage disposal when I cranked it down. Still, I put it back in the car because it promised to be a little more grabby.
Jim