New to this forum so if this has already been dicussed sorry. I just pickedup a '07 GMC 2500 LBZ crew cab, srw. I want to get more hp, and mileage out of it but dont want to spend too much and dont want to void the new 100000 mile warranty. I have only been get about 12 mpg with it, its been pretty cold though lately, temp hasnt been above 15 in a while and had many days below zero. What mods would you recommend? Intake or any programmer? I want to make it loud so I was trying to stay away from an exhaust. Any help would be appreciated.