please pardon what is probably a stupid question: i just switched to synthetic oil recently for my 6s, on the recommendation of some of you folks here, and a couple of service techs at my mazda dealership. reading the mazda faq today, i see that it says "Mazda does not recommend the use of synthetic oil." can someone tell me why the company (and owner's manual) say one thing, and the service techs at the mazda dealership say something else? which one's right? i can't imagine synthetic oil would be bad for the engine. does mazda america just want us to buy cars more often?