I've been reading this and have a few thoughts. My first Model IV started flying in 1998 and I used mogas except on cross countries for nine years. California mandated all mogas have 10% ethanol in 2004. The original tanks were kreemed, and I re-Kreemed one tank bacause of some discoloration on the fabric below the tank. I then flew until late 2007 - three years with ethanol containing mogas primarily. My new Model IV has the Denney Aerocraft tanks with Kreem. I am using 100LL primarily because my flying is spotty and I have had serious issues with the mogas in infrequently used garden equipment and didn't want the same type issues in my Kitfox. I do use Decalin with the 100 LL. Then an article in the last issue of Sport Aviatrion - page 120 - talks about the pros and cons of mogas vs. avgas and in the article it mentions that the new Shell - Sport plus 4 has additives that keeps the tetra ethyl lead in suspension. It makes me wonder if the additive Shell uses would preclude the need for the Decalin. In other words, since Shell is adding an additive to the recommended oil that essentially does the same thing as the Decalin additive - is Decalin use still necessary.