Being in the modified car world since 2003, having built my own Lexus project here is my own experience. It really depends on the mentality that you choose to build your car. How much is your budget? are you willing to use the best authentic and quality parts or just start from a beaten up car and knock off parts that require a lot of extra work to get completed? Great show cars with all the fixins' can total more than 70k+ but if you're looking at cars like the Veilside Rx7 that has been in the movie, been through show circuits around the world, magazines, books, and is immensely popular and widely known, the cars market price can sky rocket because rich people will want to buy a car that is famous and well known and one off. Let's say you start with an rx-7 and maybe its current value for one in good condition is 17k+ Then you want the veilside full widebody aero parts? 10k+ Body work and paint? 4-6k+ Rims and tires? 4k+ basic bolt on engine parts? 3k? Turbo and extreme engine build parts? 10k+ Interior? race seats? steering wheels? meters and gauges? new upholstery? custom lighting? stereo? 10k Akatsuki is for the most part correct, most car builders build the entire car as a project but after this project is completed, they are looking for something new to do, now when this happens they have to sell the car at a severe loss because nobody wants to buy a modded used car at full retail price for 70-100k when they can buy a brand new, fast and great looking car like Corvette or GTR. The downside to buying a finished car is that it wasn't your own, it wasn't done by your imagination, you wouldnt know how to appreciate it, you have no passion for it, that is why everybody chooses to build their own project, whether it be on budget or what not. Hope this helps.