Got the 3.55 LS gears in mine and I get around 18-20 highway and 14-16 city. If I get on it all the time she drops way off, about 4-5 mpg less. My highway speed is about 75-80. I drive about 100 or more miles a day commuting to and from work. I also only run Sunoco 93 octane. Don't think I would ever switch to 4.10's, but the added pep might be nice. But then my mileage would drop and don't no if I could afford the gas as I already fill up twice a week or more (35 gallon tank + reserve).

 

Man, this thread is never gonna die, is it?