This is such an excellent question, and one that I have debated back and forth. I now have a base SKY and will be getting a Red Line. While I am giving the base SKY to my daughter I have said to her, "you are not allowed to trade this in on a minivan when you have munchkins. I get first dibs on buying it back whenever you decide to get rid of it." She plans to keep it for a very long time, as I intend to keep my Red Line pretty much forever. Both cars will be daily drivers.
I have done a lot of work with classic cars as a former Automobile Photographer. I photographed Corvettes that were awarded the Dontov prize by NCRS, and those guys were crazy. Stuff like, "We checked the serial number on your alternator, and the alternator was made in 1969, but your car is a 1968. While it is identical to the 1968 alternator in every way, the serial number indicates that it is not factory original, and therefore you are disqualified." But some cars passed as 100% factory original, and I was chartered to photograph them. I reserved space in a park so I could sourround them with nothing but grass. And I discovered two types of owners.
The first type drove up in their cars, proud as can be, and thoroughly enjoyed the photographic process. There was another car - trailered the two miles to the park, and then hand-rolled off the trailer with little vinyl booties covering the tires and rims. I said, "This photograph is going in the registry, and it will appear on your trophy. Are you sure you want me to take this picture with the ugly, vinyl booties over your tires and rims?" And I was told, "Hey - I don't want to have to pluck stones and grass clippings out of my treads or wheel wells."
Okay, fine. But is that really enjoying a classic Corvette? When you can't even take the booties off the tires and actually 'drive' it?
I also did work with the Porsche club. One guy got a brand new 928, took it right from the dealership and entered it in a show. He thought, "I gotta be a lock on getting the 'Most Factory Original' trophy." He didn't. He got a whole lot of points off for stuff like excess goop on the door hinges, and the occasional misalignment and ticky-tack little stuff. He argued that his car was EXACTLY as it came from the factory. The judges said, "It's not supposed to be how it actually came from Zuffenhausen; it's supposed to appear as how Zuffenhausen would want it to appear."
These experiences have shaped my handling of the SKYs. First, I want to drive them and enjoy them. The instant that I don't drive them to preserve the value versus enjoy the moment, I lose. Second, I'd like to make my SKYs appear "how GM would want them" versus "how GM built them." In other words, I'll do stainless steel lock pulls, a stubby antennae and a dual exhaust because they look better and were probably not included on the car due to cost savings. The same goes for getting rid of ugly stickers and tags off the visors and seat belts. I don't want to look at those every day for the next 30 years...
BUT - I have kept my old air intake and exhaust system in a box, which I will stuff into the attic. When I get my Red Line I am looking real seriously at custom rims, but I will keep the stock rims handy.
Should the car go explosive in value, I'll have the original parts to restory my car to "factory." If nothing else, if my car has lots of miles and too much fun behind it to ever be "factory" then I will have a brand new exhaust system, intake and rims to sell to somebody else who wants to make their car "factory original."
But when it comes right down to it, I bought the SKY to enjoy it, not to get rich off of it. So if I tweak it here or there so I can enjoy it more, then that's goodness.
