Start at 0 each time is a bit of an exaggeration. I race my M06 in a parking lot and traction is low to medium grip. Prior to each race I re-check my suspension camber settings and make adjustments to -1 in rear and 0 in front. I run S grips on rear and M grips on front. Car is more consistent than my TC.
The last time I rebuilt my shocks was a year ago. The ball diff has never been rebuilt still works perfect.
In addition I race in a field that has 1:18 AWD cars, that have much more speed, motor and grip. I consistently place 2nd or 3rd and always ahead of M05.
So it all depends to you and how you drive. m05 is easy to drive, peg the throttle, turn the wheel.. it's fwd and under steers into turns and pulls out. BORING.. m06 drives like a real car, you need to refine your throttle control, keep the rear end under control.. but the pay off will bring a smile on your face.