I'm looking at the mounting template, and the diameter of mounting screw circles is about 5 1/2". Maybe the 6 1/2" number on the outside of the box is overall. I guess I just need to take the door panel off and see.
2003 E39 M5 Lemans Blue: Truly an amazing car
1999 E46 328i Bone stock 5-speed: Beater and Track Car
247K and still running strong