Eh, I wouldn't run a 10W-30 in my car. I've used 15W-40 dino and 5W-40 synthetic (or pseudo synthetic by the standards of some). Both work fine and the latter will help with cold starts. You can usually get a gallon of Rotella T for about $20... not too bad. These cars seem to take a little under 2 gallons.

__________________
1982 240D, sold 9/17/2008
1987 300D TurboW124.133 - 603.960, 722.317 - Smoke Silver Metallic / Medium Red (702/177), acquired 8/15/2009
262,715 and counting