Toyota operates significant testing facilities in America, most auto manufacturers do because where's the best place to do long term high heat testing? How about the hottest place on the planet: Death Valley California with the only fuel commercially available being 91 octane E10 gas.
http://www.toyota.com/about/our_busi...d_development/
Saying Ethanol
is the problem is like saying fast shifts are
the problem for the DI seal failures. Design criteria is the "problem" and as @
choi0706 says, until there's a failure there's no need to do anything, it's just a noise. Ethanol is a band aid in so many ways.