I'm of the opinion now that synthetic oil is a marketing ploy. It fills the motor oil niche for people seeking the upscale purchase option. I don't see a practical justification for paying 5x the cost of regular oil for neglible (non-existent?) results. Your car is going to run fine using 10w40 for the life of the car.
When I was younger, I used synthetic oil and premium gas. I worked on my cars, washed and detailed them every few days, and used to argue to the death with my cynical dad ("oil is oil") over the necessity and superiority of synthetic oil. After I went through a few cars and found out they still run and stay reliable on ordinary 10w-40 and regular gas, I stopped spending more.
On second thought--scratch all that. When I get my Porsche, the gas tank will be filled with premium gas, it will be waxed with the most expensive polymer sealants and carnuba waxes, and the crankcase will be filled to the brim with the most expensive synthetic blend on the market.
