Not sure if this counts for Sports Tuning. The 3.5L EcoBoost and the ECU on the Explorer appears to have an intelligent fuel mapping system that will advance timing and up your HP & TQ figures by advancing the timing if good gas and higher octane is used. I live in Utah where I am at 4,200 feet. So the best I can get is 91 octane from the pump. A local brand also is offering 88 Clear which is an Ethanol free fuel at 88 Octane. The 91 Octane can have as much as 15% ethanol in it. So question is, Which should I be running (price is the same). Should I run a 91 Octane that has some unknown % blend of Ethanol up to 15% or should I run a 88 Octane with no Ethanol. Thanks.