Go with 33's. I have a dodge mega cab 6 in lift with 37's. Biggest mistake I should have stayed with 35's. It looks great but rubs real bad in the front. That rubbin gets real annoying
They should not be rubbing. But where are they rubbing? What size Dodge Mega Cab? 1500, 2500, or 3500? I can make them fit with a 6" lift no problem. If they are rubbing there is a fix and you don't need more lift or to even cut the fenders. What is the wkeel offset on your rims? Are they stock? Shops are bad for selling wheels that almost fit just to make a buck.