Ronn,
Get replica speedster seats, as opposed to the cut-down 914 knock-offs that Vintage specs. The speedster seats sit much lower in the car, and position your torso further back. I had a car with the 914 style seats modified to slide fully back to the rear, and I still wasn't comfortable- my head was in the wind, it just didn't feel right. Getting lower in the car means I look through the windshield, driving with the top up is an option (I can almost see out the side curtains), and I'm comfortable with a couple inches to spare behind the seat back. John Steele at JPS makes his own seat tubs- they look good, they feel even better. Russ R. at Fibersteel also makes a speedster seat for replicas, but if your car isn't built yet, I'd talk to John- you'll be glad you did.