I have a 2007 XE King Cab 4x4 i want better fuel economy! So I am looking to dual it fully out and ad cold air intake. So truthfully what are the best combinations for mufflers and cold air intake. I need 2 mufflers and 1 cold air intake and any other suggestions to up the fuel economy. I am getting about 14.25mpg for highway driving on average. the problem is I drive to much about 500 to 700 miles a week. The truck is 6 months old and has 13000 miles on it. So any help would be great. Also I have searched and read the threads and still have no clear definite answer.