Adjust wheel arch when not using standard tyres

Beware, if you've not installed the standard tyres on your M5 in the back (that are Michelin Pilot Sport or Dunlop SP 8080), you'll experience tyre touching the rear arch when people seating in the rear and trunk loaded, on bad roads.
I've Bridgestone S-02 installed and had the left rear tyre well damaged by some touch !
A specialist told me that, especially the Bridgestone tyres, are larger than other for the same official size (275), a difference of les than 1 cm is enough to be a dangerous problem.

So check you've the right rear arch adjustment done according to your tyres !