I installed the factory M springs & sways on my 535im and have been happy with the ride when combined with the Boge Turbo Gas shocks/struts. Seemed a bit stiff over bumps when new but after a couple thousand miles it has smoothed out nicely. The roads here in New England are as bad as you will find in the U.S. so if they work here they should be comfortable anywhere. The M springs give you a nice look at the wheel arch without dropping it too much.