Roger, Don't get caught up in all of the silly debate about synthetic vs dino oil. Put it in this perspective. When the oil companies were done with the R&D on synthetics. (BTW, they have been around for quite a while. Used for many years in jet engines and other high temp applications). If there was the least concern that synthetic oil would eat seals, etc, then if they released it for automotive use, they would have been setting themselves up for legal problems. Synthetic oil has a better set of additives and is more viscous than "natural" oil. Can go longer between changes. That by the way is an issue that will always be debated, ie. how often do you change the syn oil. Go ahead and change over, if you feel strongly about using syn. You will do no harm to your car. If changing were a problem, then all new cars would have to be redesigned for syn and we would have warnings about the danger of changing. I think there are a couple of high performance production cars out there that come from the factory with syn. I use Mobil 1 in my 87 300E with no problems other than having to keep my wallet out longer when I change the oil
... Don't worry, be happy. Syn oil is not a new development. It's been around for a while, and I don't think it will eat your car.
1987 BMW 325