Well, for once you and I disagree! I'm a big fan of Mobil-1 despite the fact I still change at the recommended interval. I did some research years ago with mixed results: some sources claimed clear benefit, while the most negative simply said the results were not conclusive. I think SO much of the wear-and-tear on an engine is in the first few minutes after a cold start. Synthetics flow so much better at cold temperatures that I'm willing to believe in them. I'm willing to spend $400 extra over the life of the car (assuming I keep in 100K miles) for the peace of mind. YMMV.