Sorry if I rubbed some people the wrong way with this, my thought was the end result when you take the legalize out of the equation was no different then trading in a formerly tuned vehicle, but I see other people's points. I think I am going a different direction now. I am going to see what the 2019 Explorer brings. If the sport comes with the 400hp 3.0 liter, I will leave mine stock. I can then upgrade to it at the end of my lease, and get the additional power I want without a tune. If the 2019 is not a performance upgrade from what I have, then I will just tune my 17 since I do love it and just buy it out. That eliminates all additional concerns beyond potentially voiding my warranty, and one way or other gets me the additional power I want, even if it means being patient and waiting till the end of my lease.