Thats a good point jjtarnow, your car should remain within a reasonable value spread based on it's cost. This assumes you have a reasonably outfitted car within your chosen price range.
Theres been an interesting discussion about the high end Kirkham values lately. My take on it is: If you opt for the all 'bells and whistles' your going to loose more on the value come resale time. Stainless steel frame? May not increase the value much beyond what the standard frame car would bring. Billet 'everything'? Again, don't expect a big return here.
Like a house, there are certain things that return more value than other 'upgrades'. Bath and kitchen remodel? 80% return, generally speaking. Enclose the garage and to make the living room bigger? You'll take a beating on resale compared to your investment dollars for the remodel.
Replica Cobras? An auto trans will dramatically drop the value. A GM engine? Even worse. HOWEVER, what if the auto trans and GM engine were dirt cheap to begin with? Eh, maybe not so bad when you crunch the numbers. After all it's real difficult to figure out the dollars value of the 'snickers', 'yuck remarks' and 'weird vibes' that surely WILL accompany such a car. But trust me, you WILL get tired dealing with the remarks (what we have here is a 'story car').
You could make the same case for a 385 series engine, in some respects it makes your replica a 'story car'. "Hey, is that a real 427 under the hood?" Uh, well, that is, mmm,,,
Some things matter more than others (bath upgrade vs garage upgrade). My ERA has a square frame, not a round tube frame. Some folks have pointed that out (I'm so depressed) then I have to go into 'story mode'.
But by FAR more people ask about the ENGINE than the frame, no stories there! Maybe an FFR with a round tube frame and a 302 with 427 emblems on the side is better? Man, it gets complicated!