Whats it worth

I was offered a 1975 Porsche 911 with a slant nose kit , done pretty well. Has an engine in it out of a 1980 911 overall the car is in decent shape with a little rust in the floors. The car has sat in a garage for the last 14 years, ran when parked. What should I pay for this and what is it worth when the work is done and driveable.


Wade