Originally Posted by MrFatbooty
The fenders and taillights are sort of curved and swoopy, while the trunk lid is slightly elevated and has square corners which then meet the swoopy fender. Obviously the effect is more pronounced on the 645Ci, but there is a bit of the same thing in the RL.
Notice how the sheetmetal around the trunklid is. Unlike on the 5/6/7, it bulges up to meet the trunk. Makes the car look much more subdued and classy.