Standby because here is the skinny. I've been looking into this for a while and am about to change things myself.
First off, 285/(60 or 65...can't remember which)/r17 are the biggest tires you should put on stock rims. Anything larger is probably unsafe. With a 2" leveling kit, you can fit 33/12.50/R17 (325/65/R17 is the metric size I think) but you need to buy new rims. 17x9 is about the most common rim. If you buy new rims, 17 is the lowest you can go but as the rim size goes up the price of the rubber goes way up so if you can, stick with the smallest rim size...17".
If you put on a 4" lift you will be able to tuck 35x12.50. That's what I'm about to do. The leveling kit is not very expensive. I think the highest priced one I saw was $500-ish. Most are in the $200 range and consist of new shocks and some spacers to go under the coil springs on the front. I think there might be some that change out the spring.
If you have more questions about this, I've done the research. Fell free to ask.