I have a 05 6.0 f350 crew cab long bed, 4:10 rear, everything is stock, 48,000 miles. I tow a 10K 5Th Wheel during the summer. Im currently getting 12 around town, 16 hwy (not towing anything) and 10mpg towing. Im not a speed demon nor do I have a lead foot. I keep my speed at 65 or lower when towing. Are there any mods I can have done to help increase MPG? Some Diesel owners I work with have suggested replacing the exhaust from the turbo back with 4" pipe, installing a cold air intake and a programer. Will any of these help? if so would any of these mods void my warrenty?
Thanks for the help