I found a guy willing to trade me a factory set of wheels and new tires for my 20's. I don't remember the tire size completely but they will be 35/??/17's. I currently have 325/60/20's. Are there going to be any issues going back to the factory wheels?

 

More than likely they will be an 35/12.5/17, those may be a tad wide for an OEM rim but many do it with no issues. The only problem you may run into is if the tires are an aggressive mud tire with large lugs, on factory rims these might allow the large lugs to rub on the A-arms.