IMHO....
I've dealt with buyers and sellers in this market trying to move cars, I've been around the BJ crowd, and I've been building and rebuilding and dealing with the high end market for the last 7 years and this is what I've observed...
70% of the "buyers" have gotten the itch from a buddy that has a cool car. They have the means to buy what they want from their chosen career path and they have tired with the pedestrian Ferrari or Lamborhini and want something "different." These are your guys that are more about shopping the price than the car. Most wouldn't know a spark plug from a seat belt let alone a quality build. If they are lucky enough to find someone to educate them they will do alright and grow with the hobby but most of the time they end up buying a piece of junk that looks shiny and makes alot of noice, paying twice what it is worth then paying again to rebuild it. This is sad because many of these guys could become ligit car guys but end up getting burned and then get out.
20% are "car guys" who while they mechanically know about cars they really don't understand what goes into a comprehensive build. They would look at one of Stielow's cars and then look at a decent garage build with a shiny paint job and while the would know that Mark's car looks better they wouldn't know why. They would recognize that both cars come with good hardware but wouldn't appreciate the subtle details that define a high end car. Because these guys also don't truly know what goes into a high end build they will typically shop price over value... but they can also be educated into why a Stielow build has more value.... usually. Please no one take offense to this... just think of all of the car guys you know that have dismantled a car to restore it and then sold it years later in boxes because they ran out of drive. Living this business just gives you a different perspective on what building a car means.
Now if you are selling a car you want someone in this next 10% to show up
5% are Repeat Offenders. They have bought or built cars themselves. They have been through the drama of buying and rebuilding a bad car. They have caught the bug. They hang out in places like Lateral-G and have educated themselves. Although they may not have first hand experience putting together every nut and bolt on a build they have seen it happen and may have been writing checks to see that it was done right. They have an appreciation for quality and will pay for it rather than go through the drama again.
5% are professionals representing clients with the finanical means but not the technical background. These clients want a car that they can turn a key and go but never get their hands dirty so they hire someone like me to go shop cars for them. Typically if a professional shows up at your door it has already been shopped against a dozen other builds and your car initially meets the criteria the client is looking for. Professionals are a double edged sword; if you have a quality build it will be documented and you have a good chance of a sale for a solid price. If it isn't you will see a lot of note taking, head shaking and grumbling under his breath and will probably never hear from them again or get a lowball offer.
It is unfortunate to say that I've seen more bad builds than I have good builds. The "no holds barred, no expense spared" tag line is a red flag for something that will likely be junk. I've inspected $250,000 builds that they couldn't give away for $100k because the build was so bad. Another red flag is when a car is sold, then a year later sold again, then a year later sold again... I inspected a Charger build at on an auction floor two years ago that was like this. My client had been following the car and kept missing his chance to buy it and when it popped up at local auction he hired me to go look at it and it was a train wreck... another supposedly $200k "nothing held back" build. Good hardware where it was visible but poor planning everywhere else. Black paint was pinholed toe to tail.... The car sold for double what I felt it was worth to an online bidder sight unseen... the same way the selling owner had bought it and he was glad to unload it for most of what he paid for it.
I'd love to tell you that a quality build always means that you will sell your car for top dollar and a junk car will always sell for junk but the reality is that there are no guaratees in this business. Beauty is in the eye of the beholder and thus goes the checkbook.
A top tier Builder name does go a long way to justifying value but if you can afford one of those names you probably aren't worried about resale. Beyond that it is really about build quality beyond the visual areas. Plan out all of your component locations before you make the permanent. Take the extra time to lay your wiring and plumbing cleanly. Minimize everything you can for a cleaner look. Be sure all the off show surface are properly painted and dressed. Use quality hardware everywhere. Spend the money for a decent exhaust system (Midas doesn't cut it for a $50k build let alone a 200k build.) Build the car rough- do all of your cutting, welding, grinding, fitting and then tear down the car for paint. Shop your Paint shop like your life depends on it... Bad paint will completely ruin all of the time you have invested. Make sure everything is 100% functional when done- no one wants to pay top dollar for a car that has to go right into the shop to fix sloppy workmanship .... and finally one of my pet peeves...throw away all of the scotch locks that come with the parts and wire the car properly.
I've rambled long enough!