By the time you buy the 6 to 8 lug adaptors, 6 wheels and 6 tires, you're out about 5 grand. Then some kind of fender flares and having them painted. If a body shop pickks up a spray gun, there's $500 minimum right there. Also if the flares make the truck wider than 80" you'll need to mount rooftop ID lamps on the cab. You might as well trade your truck in on a 3500 that has duals already. It'll be cheaper.
You'll also reduce your cargo capacity by a couple hundred pounds and who needs duals for a 1/4 ton pickup?