I went by my dealer to ask him on the price of the 10,000 mile service which they quoted at $95. Anyway I asked him what if I brought in my own oil (mobil 1) what would the price be. He said why? I told him that I've run synthetic in all my cars and perfer it over conventional. This is were it got interesting. He told me that synthetic is not recomended by the manuel, have not had the time to confirm, and that if it came down to a warrenty issue and they found out that it was synthetic it could result in a warrenty problem. Further more I asked why different dealers are charging different amounts for the same service. They said that they follow Lexus service procedure to the letter as far as run all checks,check torque settings etc. and other dealers are not doing that and that is where the cost savings come into play. So I said if there not doing what is recommened then are they not honoring the warrenty themselves? What do you think.