I read somewhere on this site about only using OEM Mercedes brake rotors, especially important for the fronts. Their claim was that even by the same manufacturer, the 'Benz OEMs are better.
I my decision to replace the worn rotors on the 300E I chose cross drilled ones that obviously did not come from Mercedes. So far I really like them. Going through water is great, hardly any wait for water to clear. Fade is never a problem.
Regarding springs, yes they do wear. Mostly rears though from my experience. I would check your suspension bushings as part of your planning. Worn bushings can make your car sit weird and also alter ride height.
I was told by a Mercedes tech that ride heights are determined by suspension arm angles. If correct, then it is the sum of the parts: bushing good and not oblong in wear, spring pad thickness and springs are within specs, and then there are the shocks.
I measured my car and it is within that 15.5" front and rearů. But it looks and feels like it is riding too tall. It has full front and rear spring pads ( 3 bumps / 4 bumps). I need to change the spring pads.
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)