I set it low enough so that If I have a regular soda can, or a regular size drink, it doesn't interfere with the opening of the door. If I have a large size drink, a snapple bottle, or anything taller, it get's in the way. You can attach it lower on the door to not interfere with the handle at all, but then it's so low that it may interfere with the full access of the storage pocket on the door. I put my cd holder right there, and it was important to me to have full access to slide it in and out real nicely.
I just pull the drink out before I open the door, return it to the holder, then close the door. The cup holder is spring activated so that it 'clings' to whatever you put it in. When you close the door, your drinks doesn't fall over.
Also, when you mount it with the four screws, use the screws they provide. They're not very long, but they don't need to be.
Almost the whole area is wood, and that 's what you screw into. Someone above mentioned sheet metal, but you're not screwing into sheet metal. I've had one liter water bottles in there and it's as stable as a rock.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".