Seafoam for me also. I have not treated the Benz, but in other cars I put some in the fuel. And for a deep clean one can for the intake. Just before an oil change I will put some in the crank case. But I put so little it probably does nothing. I just dont want to thin the oil out too much.

__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car