One video I received with my car stated that BMW "engineered" the sound of the wipers to give the driver audial feed back (seems visual feed back should suffice to me). My car's wipers make a muffled noise which hasn't really gotten under my skin, yet (I live in Seattle). However, what I have found unacceptable is that the wipers tend to splash water on the window as it passes through their stroke so the window is never completely cleared. I've never seen this on any other car I've owned.