I own a 1988 Subaru Sportswagon and i love it, but it only does 7km to every litre of fuel that i put in it. Does anyone know what i can do to solve this problem?

ounds like you are talking about a GL turbo wagon.

I have an 87 Turbowagon thats been somewhat modified. I get an average of 20 MPG when everything is functioning correctly.

Better than stock intake is good. Better exhaust is great.. it will actually increase your mileage quite a bit.