well i guess i have you all beat , sence i owned my srt6 I have driven 11000 miles,, two years this month
the average for the 11000 miles is about 11 mpg the best i have gotten ,on a 400 mile trip was 16 ,, and of course the last tank full with my new rear end installed (stock rear end just replaced it) i got about 6.1 mpg so
average mpg 11
best mpg 16
worse mpg 4

jim