I think it has enough room but I did not buy a fifth tire, since I wanted to eventually do dual exhaust. Road noise all depends on the type of tire. Mud terrains are gonna hum like crazy since the tread goes against the grain of motion. This is good for biting out of thick mud and deep snow, but not much else. My tires (Cooper Discoverer S/T Maxx's) are a mix between a mud terrain and All Terrain. They hum on the road, but are not obnoxious. Personally I like Cooper Tire, but Wrangler Dura-Trac's are good, as well as Nitto Terra and Mud Grapplers.
If you just want the look and do not plan on wheeling the truck very hard, stay away from the mud terrains and look for the step below. I chose mine because I knew that mud terrains and ice were not usually a good combo, and we face a lot of winter conditions here. I love these tires and would probably buy them again.
Another thing. Don't let me discourage you from doing wheels, nothing looks meaner than a set of black rims with some good tread, and you can usually get them as a package deal online. Just don't expect much other than aesthetics and better off road performance. There are other mods you can do to achieve better gas mileage, but unless you go with low rolling force Prius tires, the rubber will probably not help.