Well, I originally started out with just a PI swap in mind, but I came into some extra money and everything snowballed from there.
I later decided that since the Mustang and the Cougar shared the same powertrain, I would just swap everything into a Mustang later on. But now my sights have been set towards a 4V/ 5-or 6 speed platform, so I'll pretty much need to start over from scratch with the parts anyway.
Keep in mind, that includes the cost of the car. Take the cost of a Mustang, then add the same parts that I've got into my car into it and see what kind of number's you come up with.