I went through this when I bought my wife a 300CE last year with 142K and cam up to the first oil change. After much thinking a research, I came into the Larry Bible camp...change it hot and change it often. I have always done oil changes on all of my cars at 3k and am sticking to it. I run Valvoline 10-40 and have not bought onto the hipe about synthetics, and do not believe that leaving oil in the crank for 7-10K does the motor any good. Also, taking time to do an oil change give you the opportunity to check the car for other problems.

Antonino