Mine has the "Full Banks Package", Intake, headers, mufflers, pipes, Trans-Command, and chip, and although I have a lot more pep than my last V-10, I don't even see 1/2 mpg more. Did I say a lot more pep?
I never even go 50 miles without one of my Jeeps in tow, so factor that in as well.
2005 Georgetown 342DS XL, Full Banks Package
2005 Liberty Renegade 4X Toad
1989 Wrangler Sahara Toad
1984 19.5' Beachcraft i/o 5.o liter, 4-bbl (and you thought your Moho sucked gas!)
D/W Carole and Maggie the Teacup Lab (Black Chihuahua)