O.K. Thanks for all your input gentlemen. I suppose I didn't state my question clearly enough.
I was trying to see if using Dino Oil in my 98-E320 is safe for the car at 5000 mile oil change interval. Which in turn would lead to $160 saving per year if using synthetic (I am changing at 5K mile anyway) as I don't trust the FSS totally

However, I think we should put this thread to rest if we start getting into a major argument.

JeffreyP