My PB came with the 20s. Since I have Max Tow, I bought a set of the 18" sport wheels on eBay (super inexpensive) and had them powder coated matte black. Wrapped in 275/70r18 KO2s, which are essentially the same size as stock (33.1" diameter, 11" wide). I had a set of 35x12.5x18 KO2s on reserve...
21 Lariat 4x4 Powerboost, 9K total and 17.1 over that time. Added a Go Fast Camper a couple thousand ago and did about 1500mi of towing at 14 average. I live in a small town so it never heats up and I've seen around 13 for a tank over the winter. I've got 99% on all the "eco ratings" pretty much...