I believe that my driving habits would allow me to consider the 7,500 mile interval. I was just wondering if anyone else used that interval and had a high mileage car. I guess I should also have asked if anyone changed their oil at 7,500 miles and suffered a premature failure.
I've changed the oil on my 380 at about 5,000 mile intervals using dino oil (since I bought it at 60k). One of the guides on the single row timing chain broke at about 160k. This was most likely due to the single row design. When I repaired it and installed a double row chain, the inside of the engine was very clean with no signs of abnormal wear.
I bought the 300 with 80k on it. I've been using a 7,500 mile interval with synthetic. The engine uses a quart of oil every 1-1.5k miles. So, I may switch to regular oil and increase the change frequency.
02 E320 4Matic
01 E320 4Matic Wagon
01 E320 Wagon (wrecked PM if you need parts)
99 SLK 230