Salut Steve!
Wow, this seems to become a quite international thread!
The wheels have been welded by
http://www.felgen-service.de/ in Germany. It seems that there are just a few specialists on this planet who can do this professionally.
I have not been at TüV with the wheels so far, but I hope that they will not recognize the modification
À bientôt!
PS: For all who are not familiar with German regulations: We have to get our cars inspected by TüV every two years in order to keep them licensed for street use. And unfortunately TüV does not like modifications at all...