Dean,
Two places you may do a search of are:
1. http://www.performancemarket.com/turbo

2. Clinton recently did a 190-2.3/16V turbo upgrade and got a kit from England but made by Mosselman in Holland. I know they also have a new website but forgot what it is but they do the ML turbo kits. Check Clinton's site/forum on the subject or do a search.

Good luck

Tobias MB
4 MBs