I use OE or OEM parts ONLY! Nothing too good for my benzes.
Some parts are better oem, some parts better oe, you just have to figure out which ones.
Lemforder is great for suspension, better then dealer parts I think.
Oil filters in gas cars I use MANN and Diesel I use Hengst.
No Benzes in the stable at the moment, but itching for one again.
Former Mercedes in the Stable:
1983 300CD Turbo diesel 515k mi sold
1984 300CD Turbo Diesel 150 k mi sold
1982 300D Turbo Diesel 225 sold
1987 300D Turbo Diesel 255k mi sold
1988 300 CE AMG Hammer 15k mi sold
1986 300E Amg Hammer 88k mi sold
1992 500E 156k mi sold