That car you describe is certainly valuable to the right buyer (you) but not appealing to the masses. My '87 was similarly modified and when I decided to sell, I reversed everything to stock (I kept the parts.....
) to appeal to the widest market. Ironically, the guy who bought it plans to do everything I took off of the car.
I think the $45K price is a bit outrageous. You can get a lot more car for that kind of money. 964, 993, 996 modified or full-on race cars can be had for that kind of money and are much more formidable platforms to go fast in. As the newer cars continue to age, the older air-cooleds lose a lot of their value.