This was really bad on my 4-series grand coupe. Going over a curb like into a driveway would make a sound like it was breaking in half. Supposedly it all came from the door-seals against the windows as the body flexed. Yeah, pillarless windows...but the car itself wasn't really stiff enough or put together well enough for that feature. My SS 1LE on the other hand, same thing works fine.just rode in a coworkers s5 sportback this week and was surprised at how noisy the pillarless windows are, lots and lots of high pitched squeaks...