I went through this a couple months ago. I thought about the 19. 5s and the cost was way to much. I ended up buying a set of BFG 255/80/17 E tires, in the new style KM2 mud terrain. I was unable to find any other tire in this size. The mud tires were more than I wanted, but they are very quiet and you would not even know they were a mud tire if you did not look. I am running them on my stock rims. There is pleanty of space between the rears. I ordered them from Discount Tire. Local tire dealers had a hard time trying to get them and were about $100 a tire more money. I am happy with them so far.
Scott