I have a 2006 gmc 1500 crew cab z-71. I am going to install a 6" lift this week with 20" xd rockstars and 325-60-20 nitto terra grappler a/t's. My question is about trailer pulling. How bad does this affect the ability to tow. I have a 29 ft travel trailer that i plan to pull to florida(700 miles) and i didnt know how the lift would affect it. I am also install a rear air bag set up. Also, what kind of fuel mileage decrease should i expect not pulling? thank you in advance for your help