As for the LT or P rating, when I got new tires I went with LT. The original tires that came on the truck were P's. The tread looked good but the side wall went and I don't tow. The ride is not as nice a little stiffer but this is a heavy truck. The two brands you picked out are both great tires I think the Mich's are a little bit better. I went cheap and went with General Ameritracks. Not the tires you are looking at but I am happy just the same.