Robert,
Your driving style at the track is non-drift, right?
If you were into drifting, or driving rallye, you would probably like a bit higher
percentage than the stock 25%.
BTW, if a car is driven with DSC off and a bit of wheelspin now and then, it wears the internals of the limited slip mechanism fast. I think there are many M5s with non-working LSC diffs, without the owner even knowing about it.
(I had the diff on my car replaced for this reason three years ago.)
David