I run Delvac 1/Mobil 1 Truck and SUV (same thing) in my TDI, but run a good dino in my benz. Don't get me wrong, I'm a firm believer in fully synthetic, however,
1. I don't use my benz in the winter
2. I can't realize the advantage of extended drain intervals on the benz due to heavy soot loading.
That being said, I don't see the summer temps in Wisconsin that you do in Dallas, so maybe it is worth it
