Just last week i installed a blaupunkt casablanca cd50 head unit ($299 through crutchfield mailorder) in my 82 320is with a/c. Although not designed for the 90 deg. mounting angle, it works perfectly and has not skipped yet due to a road bump or any other shock to the system even with the terrible road conditions in michigan. I am sure there are many other cd player head units that will risist shock like this also, just as long as you are willing to pay a bit more.