Well, I changed the oil in my Olds van today and decided to try the SuperTech synthetic blend rather than the Pennzoil High Mileage. Why? After doing some research, this oil by Warren looks to be a top notch blend that has the "high mileage" ester additives. This oil is not just rated SL and GF-3, but carries the CF rating, too. There is only one other GF-3 rated oil that I know of that also has the CF diesel rating, and that's Mobil 1. All things being equal, a CF rated oil is going to have a more robust detergent package than an oil that is just rated SL. The ST synthetic blend smells identical to Rotella T Synthetic. It is very light in color, almost the color of cooking oil. And unlike every other oil I've ever used (including Mobil 1), there was absolutely NO sediment in the bottom of the bottle. Just compare the two photos below of the bottom of a Pennzoil bottle and the bottom of the SuperTech bottle.