MB manuals say not to use any additives. Some folks here swear by Techron and just recently there was quite a discussion on a product sold at GM dealerships. I've used the Lubro-Moly fuel system cleaner and Techron. I wasn't able to detect any improvemnt in performance, smoother idle; better gas mileage.
I wonder if quality fuel and an occasional "spirited drive" are better alternatives.
1991 300-SEL - Model 126
M103 - SOHC
James Madison - Oppressors can tyrannize only when they achieve a standing army, an enslaved press, and a disarmed populace.
Liberty Firearms Training - After years of trying to regulate California criminals with a never ending stream of gun control laws they have still not given up with the belief that if they make something a crime that criminals will miraculously start obeying the law.