I am interested in a 2011 Dodge diesel 2500 4X4. However I like the 20 inch wheels on the 1500. They are not an option on the 2500. I would have to get them after market. The dealer told me that the larger tires would decrease my MPG big time. I ask him if that is true, then why would Dodge put them on the 1500. He didn't have an explanation except that's what people want. Which brings me to my question. Does anyone have any experience changing to larger wheels? Did it improve/decrease the mileage?