If your goal is to replace it in a couple of years I wouldn't put too much money into it. I would save your money so you can put it into the new truck, just my opinion, but the wheels and tires you get for the 1/2 ton won't fit on the diesel so you'll have the expense again. If you are set on spending the money then you should be able to fit 33's with your level kit, just make sure the rim you choose has the proper offset, around 20 to 31mm.