I went with 35x12.5x17 Toyo MTs on 0 offset XD Crank rims on my 2010 Sport. So far I have zero issues. I have a 2.5” front spacer and a 1.75” rear coil spacer made by Rough Country. The back end will sag a bit with a heavy load, you won’t have any issues with rubbing in the rear end when fully loaded.
However if you’re planning on over loading your bed to the point where your headlights are squirrel hunting in the tree tops I would definitely invest in some airbags such as the Airlift 1000. I would be more concerned about how your truck handles instead the amount of sag in the rear. It’s better to be safe than sorry. The Airlift 1000 will be my next MOD for that very reason and for the $150 bucks it will cost you why not?
Here is the link for the Airlift.
I attached some pictures so you can see what you’re getting into with the set up you’re planning on running. Keep in mind you will have some extra rear tire clearance compared to my set up since I only have a 1.75” rear spacer.