I just got a 4 inch skyjacker lift with 35x12.5R17 toyo m/t on my 2005 5.4 XLT f250. I knew before that my fuel economy and power would be lost. As of right now I am getting somewhere between 7-8 mpg in the city and about 11 on the highway empty. I also pull my boat which is about 7,000lb. Before I had the lift and had my stock tires, my truck pulled the boat okay. Now I cant keep my truck above 55 without downshifting while pulling the boat. I was reading other post about changing the stock 3.73 to 4.10 or 4.56. I know if I get 4.10 my mileage would increase a little bit, and probably bring it back to stock performance. Would that be the case? Do I want to gear lower to make up for the lift? Would it kill my highway mileage?