I have a 2012 crew cab z71 5" rcx lift factory 20's and currently running 295/60/20 trail grapplers with factory 3.42 gears, hypertech max energy on 87 tune, and magnaflow exhaust. I do not off road and very rarely will i tow anything. I have noticed with these tires my 6th gear is pretty much useless, so i have been just putting the truck in M5 and driving. I am avg. about 16 mpg right now. Is it really worth the $1500.00 to regear to 4.56 gears? Would my mpg really go up much? I have also been debating on going down in tire to help instead of gears and maybe this would allow me to use 6th gear with my 3.42s, looking at a 275/65/20 toyo open country at2 since truck is never off road. Thanks for your help!