CharlieB "Fact is, if an additive is used and it changes the chemistry of an API approved oil(and it will), you will void the engine warranty"
This is protected under the federal Goverment. A manufacture must prove beyond a reasonable doubt that any aftermarket part that is installed on a vehicle was the root cause of the failure. It doesn't matter if its api or any other kind of oil as long as it meets the oem's specifications you will not cause any harm. If you read the owners manual they say we do not recommend the use of oil or fuel additives. Keyword is recommend nowhere in any vehicle that i've owned does it say adding any supplements or additives to fuel or oil read using these products WILL VOID YOUR warranty. And you will win in a court of law a suit if this subject was to arise.
If you use anything with the words racing on it now that is a technicallity that they can get off the hook from. Which SFR nor many others have. In fact SFR has their own warranty that extends the original OEM and in the fine print its cleary read racing offroad and abuse is not covered.
Let me ask you this CharlieB What is a better oil. Define what a better oil is after the smoke clears additives are the only thing you'll have to fall back on because the only things that have made any improvements to oil is the advancement of synthetics from Dino oils and ADDITIVES.
If the OEM's had it their way it would say use ford oil or nissan oil. They make cars not oil leave that to others. They depend on others to make their vehicles just like oil people depend on additive people. Their are some giants out there that make their own like Texaco, Cheveron, Exxon. But even they look to the additive people.
STP made zddp the oil guys hated at first now you find it in almost all Aftermarket oils QS,mobil etc.
I think the biggest things with additives is the lack of knowledge and education most people haven't tried them. Those that have and think they have an opinion haven't tried enough of them.