If one had to order a body off and nut and bolt restoration...matching numbers...change original colours...
does this impinge heavily on the actual resale price?
People change colors all the time, to suit their tastes. Color is a very personal preference, and certain people and in fact certain parts of the world don't like certain colors. For example, 568 Signal Red isn't as preferred in Europe as it is in North America, as such a bright red color just isn't appealing to Europeans as much as some other colors are. Along those same lines, whitewall tires are more prevalent in North America than Europe.
I changed my car from what I considered to be a ho-hum 050 White to 568 Signal Red. It's a stunning color, and a well done job. Would I do the same color again today? No...tastes change as well, mine included. I would probably go for a dark blue. No wait, that Tunis Beige has always looked fabulous...If you ARE planning on a color change, what will be valued is if it is done properly. I've seen too many done haphazardly where the dashboard metal is the original color, and the outside the new color. I've also seen some clearly un-original colors, such as an "Electric Lime-Green Metallic" I once spotted at Dan Caron's place belonging to Canadian singer/songwriter Ian Thomas. That would raise the hackles of "the peanut gallery" at a BaT auction!
I changed the interior on mine to all black, mostly for one reason: the vast array of interior colors once available when our cars were new had been whittled down to nearly black only when it came to some interior bits. So, I went with something that would be easy to source. if you seek out posts from
AlexD, or look at his story on his struggles (and eventual success) in sourcing a gorgeous turquoise carpet, you'll get the idea of what I was trying to achieve by going with a black interior:
avoiding Alex's efforts.As for "numbers matching" this has not been as much of an issue as it has been for certain cars, particularly some American Muscle cars. What IS important, is the right engine in the right car. A Ford small block V8 engine in a Pagoda? Kind of frowned upon. A sedan engine? A 230SL engine in a 280SL? Those are the kinds of things that can raise a flag. Remember, the newest of our cars is 50 years old, and somewhere along the line there might have been a dealer engine swap with a reman from MB. Now the "numbers" don't match. If it's a 280SL with a proper M130 motor, probably not a big issue.
There's a school of thought where "all original" (meaning unrestored) is highly valued, but if someone values that they'd probably never consider a fully restored car in the first place. There are these things called "sympathetic restorations" where only the barest minimum is done in order to preserve the age, the patina, the signs of a 50 year+ life, but making it safe to drive.
Before you invest the big bucks in such a bespoke restoration, regardless of color choices, may be a good idea to live with the car for a while. Maybe you will not like it at all, maybe you'll learn a lot about it as you drive it and maintain it. You can always send it away for restoration.