I have successfully run up to ET37 offset on the front (and back) of my '87 300SDL. It is not an optimal configuration, but works without rubbing. As far as spacers are concerned, I have H&R DRA-Series spacers on my car and they are great. They are not the "slide-on" type, where you need longer lugs (junk, IMO), but rather, the spacer bolts to the hub with supplied bolts, then you use your stock lug bolts to attach the wheel to the spacer. I have run well over 100,000 miles with these and have had no issues whatsoever. I have run them in front and in back. With a 17" or larger wheel, you can get away with more offset on front. A 16" wheel with a higher offset will hit suspension parts in front, thus the need for spacers. That being said, it is ALWAYS best to keep the offset where Mercedes designed it to be (whether with spacers, or the correct offset wheel), as their engineers were pretty smart guys...

Rob

 

H&R lowering springs17*8 Mandrus with +25 offsetContinental tires 225*45 R17

 

That is Beautiful