I hate to make you guys envious, but I get on average 23 MPG in my 1999 SL500. It was on of the reasons I chose a later model SL. Even with some now and then agressive accelerations the mileage is even better than my 98 Ford Ranger, which only has a 3.0 V-6.

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1999 SL500 87K
1994 E320 112K
1998 Ford Ranger - the daily driver 274K and no major repairs (an indestructible truck)
1978 Pontiac Trans Am 110K
1977 Pontiac Trans Am 130K
1999 SL500 87K (the garage queen, only out in the summer)