I am somewhere in the middle, I like to preserve the look and feel of the cars as they were built, but have been known to do some modifications. Most of the cars we drive were built by the thousands, so I don't see a need to treat them as historic artifacts, if I had a one off le mans winner or something I might feel different. Your car, your choices, I do sort of feel if you are going too far with the modifications, modern seats, engine swap, air conditioning, etc. etc. why not just get a modern or relatively modern car that has this already, but I can also understand liking the looks of the old cars and wanting something a little different, bottom line, your car, your $$s, your choice. One thing I don't like is calling a car that has been modified in some way as "not correct" or saying that something is "wrong" with the car, simply saying not original is probably more accurate and less insulting to the guy who spent a lot of time and money fixing it up. Of course representing something as "completely original" when it is not, is just as bad if not worse, do what you want with your car, and describe it honestly.