If it was for the later Mercedes, say 1990 and later, I would get the Baum CS 2000...It is the BEST HHT for Mercedes in the aftermarket. Cost? about 3-4k,
If it was for the earlier cars, I would get a good SUN 400 or something equiv. Scope. They are about 10k.
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS