so I'm late to the party here but I will throw in my 2 cents. I have a '17 platinum running 2.5 kings and 35s (315/75-17s (Raptor tires) and I love it. there has been some decrease in milage I'm sure, but it is a little hard to calculate since I can't update the tire size in the computer to get accurate MPH or MPG readings. My truck is leveled and not lifted but I did have to cut off both the crash bars in the front wheel arches. I really love the setup and have not noticed any performance issues with my 3.5 eco. I attached a pic just cuz... Good luck.
