I'm not being combative, but I really have to ask: why? Why does this "taillight feedback" help?
For regen, (on M3) there's a big bar on the top left of the screen. And, for regen or TACC braking, why would looking down at a screen be worth more (safety wise) than actually looking at the cars in front of you? What is the screen telling you (and I mean "you" in the general sense, so don't take it personally) that is worth taking your eyes off the road or the cars in front of you?