It shouldn't hurt anything. It's mainly there as an economy button, even though it says power.

You might be able to find a chip or other programming device aftermarket that would allow you to operate in economy mode (with the settings as they are in power mode now) and a hotter power mode that will make a bit of difference.

I've noticed that a lot of these import SUVs benefit in the fuel economy department with the addition of larger tires. I think it has something to do with the larger tire diameters helping to get the already high numbered rear end gears back down into highway friendly ranges.