I get about 11,5 mpg if I get on it...and about 13 IF I stay out of the turbo. So your mileage isn't out of the average if you kee your foot your foot out of the accelerator!! Some folks seem to get better mileage, but they must be tuned more critically.
1987 factory Slantnosed 930 Cabriolet/Guard's red
2002 Midnight Blue 996TT X50
1999 Iris Blue 996 (Dash fire burned and totalled 9/07)