Your total of 1900 is a little off. You cannot price a standard setup, and include a rack as well. That does not work. So your 1900 just dropped to 1400. Now I did nit do it the other way keepingthe rack, and removing standard steering, but let's assume it totals 500 as well. So if you source all the suspension parts, that come with the alterkation, and it totals 1400 that leaves 3600 for the k member. As that was bassicall all you did not have in your post. Take off 880 for wilwood brakes, and your at 2720. So your looking at 2720 for 200 in steel tubing and a weld job. When like I posted earlier you could get a comparable part for 500 for another brand. I don't see where your thinking that it's comparable to other stuff.
Also you numbers seem a little high. I have priced chris Alston stuff at $2000 but it needs brakes. So ad in another 880 give or take. Still no where near the alterkation. I called heidt's about installing Thier kit. Thy recommended the truck suspension to get the track width correct, as well as frame dimensions. It was ~$3000. That's complete just add wheels. So again your prices seem high no all your compairable parts. Unless when I called and spoke with them I got some great deal, but I doubt it as I went with the price off the website. Let's debate it. And understand the viewpoints from both sides.