VG30E gas mileage?

I'm considering buying a 1987 200sx with the VG30E V6 engine. I have searched extensively but have not been able to find what kind of gas mileage these get. I've heard estimates between 15 and 23 combined in the Pathfinders, but a smaller car with a more aerodynamic shape must get slightly better mileage than a 4x4. Any information would be appreciated. Thanks.