Mobil 1 Regular Synthetic and the Extended Performance Synthetic. Both are 10w-30 Anyone know if there is any difference other than the labeling? I have gone to their website and there is no real info, just adspeak. Could the increased price have something to do with the advertised oil warranty of 15,000 miles? The available spec sheets on both oils are nearly identical. Differing only in the viscosity and pour point. Any special elements in the more expensive extended version. I am only using this in my old DD, the 92 Ford Explorer with 95K on it. And I change it every 4K.