I was like you with my 300E. I used to burn an a quart of a oil a week. I went and had an oil change to Chevron 20W50 with a bottle of Mobil1 Tri-Synthetic 10w30 thrown into the mix. I found that oil consumption was reduced to once every three weeks with extremely aggressive driving. I am not the first one to realize this cocktail decreases oil usage. But, I am only prolonging the inevitable of valve seals .