Today I switched out the ug bolts on my smart. I replaced them with VW rabbit GTI bolts. They share the same thread, shoulder, length,etc. but use 17 mm head ( 11/16 fits) Now any of my 4-way lug wrenches fits. The GTI lugs have the black plastic caps. Not a big eye-catching mod, but maybe useful someday. Now if I can snag a used wheel on my trip to Germany this week, I'll be set.