In times past....we used to replace the exhaust studs on 911s because you could easily destroy a cylinder head if it broke and took some head material with it. This would also cause a partial engine teardown.....expensive!
So the trick is to find a one meter length of threaded stainless steel metric rod and make your own studs but still use the copper BMW or VW nuts with them. This always works no matter how long the nuts are on!

Tobias MB
4 MBs