Ethanol blended fuels will always reduce your average MPG because ethanol has less energy than gasoline which requires more of it to be used.
Power gains/losses between octanes are marginal at best. On older engine management systems you won't see much of a gain unless you change the spark timing yourself with a tune.
2011 SES 5spd #006 >> SR #213
What other people think of me is none of my business.