My M5 makes a bang noise when the rear suspension bounces hard over very abrupt bumps at highway speeds. Only does it over few of them, I can usually tell if it will do it just by the shape of the bump. To me it sounds as if something is moved/thrown up and down ( I suspect something like the mobility kit or the middle rear brake light). Last time I brought it to the dealer they said it's normal,it's the shocks because the M45 is so stiffly sprung. Today I drove the loaner 135i over the same bumps that cause this noise and the little 135i reacted to those bumps with more poise than the M5. Much less noise and drama. Mind you the 135i has the M-Sport package with the stiffer suspension and 18s and obviously it had nowhere near the insulation that the M5 has and yet it was much quieter. Now, how do I make it more clear to the dealer that the M should be quieter over bumps than the 135i? Do you agree that that should be the case?
Thx
Thx