All mercedes and crossfire lugs are "BALL" type.
most aftermarket are acorn "TAPERED" type,

that is where the lug meets the wheel,,,,,, tapered wheel (only use tapered lug) (same for ball type.)

with the wheel off the car stick the lug through one og the holes,, you should have about 5/8" sticking for the rear ,,,,the front does not matter as long as you don't have more than an inch or so,,, jim