If the owner's manual recommends oil change every 7500 miles for 300E and 5000 miles for 300D then why would anybody change oil at 1500 or 2000 miles.
I have been changing oil every 7500 miles 93 300E with 140000 miles. 5000 mile change on 87 300D with 220000 miles. I bought these cars three years ago. We drive about 100 miles every day.
Engines are very clean and no problems. I just use regular oil with correct ratings.