Thanks! Sorry for the late reply...just saw this.
i have also heard they modified the sound created by the exhaust when in the cabin to sound more throaty... so what does that tell you...

Overall i would still update the exhaust as I like the rumble, it does sound much more powerful and you can also hear the turbo more ... but maybe do a custom magnaflow or borla solution. This was also not a kit but a custom exhaust replacement and resonator delete. They do not make kits for Expedition ELs yet that I know of.
A very slight increase in gas mileage... about 1mpg better.
Truck is lifted with ReadyLift strut spacers.
I updated my signature with tires / wheels size.... I did increase from the stock... but not much ... i think they work out to be about 33.5" tall.
Thanks, I had done something similar on my previous 2014 Expedition Sport I had that was also white... which prompted me to do something similar here.