There were problems with the first synthetic oils used decades ago. If I remember correctly, they were not compatible with Dino Oil and would cause problems. When companies first put detergents into oils it caused problems too, but now everyone puts detergents in their oils. Synthetics flow easier and have better additives so sometimes they flow past seals that held dino oil back.

ALSO, Dino oil can cause seals to swell which can increase wear on the seal. Since synthetics don't cause swelling, the seals sometimes shrink back and can leak. You won't know until you switch. I switched to synthetic at 70k miles with no leaks in my car.

Lots of superstitions surround everything synthetic. Look at the facts. You have a non-turbo engine so it's not as critical to move to a synthetic oil. Synthetics do provide additional protections and tolerate extremes better than dino oil. If you are doing the 10k mile oil changes then I definitely suggest the synthetics and 5k oil filter changes since I don't believe that the Dino oil can last that long. 5k miles on Dino oil in a non-turbo...I can live with that.

Bottom line...it's your money and your car.
--
Nathan Valles, Black 855R, Tint