Did you check the tire pressure? I found that my car was delivered with the tire air pressure way off. Resetting the tire pressure to normal, changed the behavior of the car for the better in a major way. I also think that runflats underperform a bit in the stability dept at these high speeds. If you think it's active steering (which is correcting for crosswind, and you have to learn to trust it), you can turn off DSC and it'll stop correcting by itself. Above 70 or 80mph, the steering ratio does not change.

The other thing I'd blame (which is supposedly addressed somewhat with the latest update) is that the servotronic power assist is way overboosted for my tastes.

Thanks,
Dave