"new" 1969 Barracuda

A big x2 to what Mopardude318 said. You'll find most of us on in this board aren't purists ... we build them how we want them to be: individual works of art that are up to today's safety standards without the air bags and computer controls. A 25-cent part won't leave us stranded on the side of the road.

These cars -- and all others -- are worth only what someone will pay you for them. "De-value" is a subjective term. One thing to consider in replacing / upgrading original parts is to keep the old ones in case the person you eventually sell your car to IS a purist. It'll sweeten the deal for them that much more and allow them the option of putting it back the way it was.