There is no mention of any better steering response at higher speeds in the following video for the relatively new 7 series, and I've not read of any difference between IAS in the 7 and 5 series
http://www.bmwusa.com/Standard/Conte...+gRO1AkEqBnQ==
Sharper steering response is brought about by the sport tranny with dynamic driving control toggle button in sport mode and/or dynamic drive tightening the chassis. Dynamic driving control is not the same as dynamic drive and the long route taken (including checking with BMW Germany) to understand these options are in
http://f10.5post.com/forums/showthread.php?t=368952
However, I am open to IAS bringing about sharper response if this can be substantiated.