The center caps that came with the CLK wheels would not work for
me. I "dented" in the caps as much as I dared with a ball peen hammer
.
Then I used the caps from my bundts. It has worked so far, even though
the front bundt caps almost don't seat. Maybe a .030 gap. But they have
in fact stayed in place just fine so far. These are the wheels I thought looked the most "OEM", imho.