if your talking warranty then you shouldnt put an Air filter in the car because technically they can try to void the warranty.. Just giving you my 1st hand experience using ethanol for the last 3 years all in cars not approved for ethanol use and thats even E99 as well.. Not what the internet or my manual says.. The manual also doesnt suggest running 1.5 Bar of boost on a stock motor but we know it can be done reliably..

Im not trying to market anything just trying to share some experience with the community for FREE.. Run what you like.. I like to be in front so i run E85..

 

Ethanol is a hydrophilic additive and absorbs moisture more rapidly than straight fuel. If you drive frequently and notice improved performance with the ethanol, then you are probably fine; however, if the car will sit for any period of time with a less than full tank, I would advise against ethanol.