I maintain (own, but not drive) three vehicles, a 2004 Honda Accord, a 2008 GMC Acadia and a 2008 Toyota Avalon. I’ve used Lubrication Engineers LX-2300 with good results, increased gas mileage, better used oil analysis, and a general “good feeling”; I am currently experimenting with Schaeffer’s Soy Ultra with no increased gas mileage, and no “good feeling.” The Schaeffer’s came with one of the bottles leaking and the packaging really looks cheap. I have a case of Red Line SI-1 that I haven’t used enough to comment on. I’m not very interested in Marvel Mystery oil as I used it in lawn mowers and mini bikes as a kid. Does anyone here use Red Line on a regular basis?