That is very interesting.. The guys down at the Dealership said pretty much the same thing to me, and said that the only real crap comes from running cleaners thru our gas and oil systems. On the subject of fuel injector cleaning, one guy said if you use a good quality gas w/ detergents, you should not have to have injectors cleaned, but went on to say that since a lot of people buy cheap gas ( ? ) and than run products like STP etc thru the tanks, a lot of crap can build up. He also recommended a flush like the snap on tool flush that hooks up to the fuel rails in a FI engine, and said once a year or so (depending on driving habits) was probably plenty, if that.