I far from "drive like a granny" and mines still high, my trip computer reads 42.7 mpg for my driving, so I say around 38. The car has always been well serviced and maintained so this would have a positive effect.
most 8v's are not economical averaging around 26-35 miles ,better off getting a diesel like me 50 mpg on a crap day and 67 on a good day.