I have never driven E70 with adaptive drive, but I have never reached the limits of my 35D (without AD)even with 70% more power now. I am pretty aggressive driver and always pushing on mountain roads and freeway ramps with no traffic. The grip is just stupid and it will outcorner 95% of the cars on the road any day. I dodnt believe that added complexity and expense of the AD is worth it.
I actually adaptive shocks delete on my wife's '09 Z4 after they leaked after 40k miles and $850 a pop is the best price I was able to find.