6J Porsche Cookie fit ? what about Merc wheels?

[dubdubz]

You also need to think about nut/stud size and also the centre bore may not be big enough.

granted mercs are generally12mm so will need reaming out, I believe the centre bore is large enough in fact there is a spigot kit for t4's [modern version]

http://www.performancecarshop.co.uk/666mm-571mm-spigot-rings-mercedes-wheels-to-vw-t4-p-39.html" onclick="window.open(this.href);return false;
so I take that to mean that their centre bores are mainly 66.6mm????