How about the enjoyment factor. If you buy the car and can't enjoy it, or it's uncomfortable to drive, why have it. If putting in air makes you drive it more and increases the enjoyment factor, who cares about what you sell it. You only live once and unless you're buying a concourse blue chip car it shouldn't matter. Buy what you like, drive it how you like. That's my 2 cents. Did that with my 66. Did the mods that I enjoy, not what the value it will bring down the road-