Check your spring pads. The rubber bushins att he top of the springs.
Witht he wheel off, you should notice some little bumps on the pads.
1 bump = the thinnest pads at 8mm
2 bump = 13mm
3 bump = 18mm
4 bump = 23mm
If you have the thinnest pads you should be able to change them out for thicker pads.
I have the set of OE Springs from my 1992 300CE if you want to buy em I'll sell em to you. My mech lowered my car for me using the neuspeed springs I bought. He ended up using 2 bump front and 3 bump rear pads, and the car sits perfect, and only rubs if I hit a heavy dip in the road at high speeds. Otehr than that there is no rubbing.
Your car might just need some thicker spring pads, so check this first, though labor in changing the spring pads will probably be the same as labor involved in changing the springs along with the spring pads.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.