The bolts on the front calipers were TIGHT. Had to go with the low-tech impact wrench (open end wrench and rubber mallet) to loosen them.
Also, the rotors were worn, with a ridge around the outside, which made removal of the caliper more difficult. After puzzling for a bit, compressing it to open it a bit allowed me to slip it off.
1992 300E Sedan, 1999 E320 Wagon