I have 235-65-17s on my Badlands. The consensus seems to be that 245-65-17s are about the biggest, lift or no lift. It looks like the limiting factor is the size of the wheel wells.
I have orepurchased my oil changes with the upfront service plan. This of course uses Ford's synthetic blend. The dealer tells me that I can use full synthetic and only pay the difference in the actual cost of the oil between blend and full synthetic... $50 extra per oil change!
My Badlands is way down in South Texas... pretty hot summers... dealer suggested every 5,000 miles with their synthetic blend. I bought the Ford pre-maintenance plan so I'll get 10 of those prepaid, regardless of price increases. At the rate I'm going, that will last me several years.