Of course there is a mechanical linkage: the Power assisted steering simply, well, assists.
My car was manufactured in the third week of April so presumably has the later rack. The handling and steering weight is great but it still wanders. A bit.
Current: 2013 F10 520d M-Sport, Professional Media, Visibility Pack, Reversing Camera, DAB
Previous: 2011 F10 520d M-Sport, 2008 320i M-Sport Coupe, 2002 325i, 2001 318i valvetronic, 1998 318i, 1996 525i, 1990 Porsche 944S2