Yamalube has their special blend of oil, which they call non friction modified. I am wondering if it is really necesary to run this oil or if any regular motor oil will do. I run it now and the guys at the dealership say its different, but of course they want you to buy it. If it is different, is there a different brand of non friction modified oil that is good enough? Whats the difference between regular oil and non fricion oil any way?