I can't tell you anything about the plow package without looking it up. But I can speak to the tires. I'd be very leery about putting 37s on your truck as is. I have Toyo M/T 37X13.5 R20 LT on my truck with a 6" lift kit. Most kit manufacturers won't even recommend a 37" tire on an 6" lift unless it is fairly stiff. As it is now, I'm looking to do an 8"coil-over system with a 37" tire later this year, just to be safe. I do plan on hitting some terrain that will use all of the travel my suspension was built for. I guess if you went down a flat road with no bumps you might be OK, but then whats the point in having a powerstroke for that? lol. The gearing you have for a 35" or even a 37" should be fine for the average applications.
I think that even if you do have the leveling kit on-board, I'd be going to a tire dealership and get them to sign off on what you want to do, then if you rip through a tire and take off your front quarter panel, they have to take the fall for it. Good luck!