Why are sway bars so expensive?
 

I pulled a front Weltmeister bar out of a parts car today, someone had modified it by adding spherical bearings around the bar just inboard of the unibody, then welded in a cup mount such that 8 bolts hold the bearing outer to the body more securely than any bar system I've ever seen. The tri-mounts seem trivial compared to this custom set-up. I did some research to see what it might be worth to put on Classifieds and was amazed at how much these go for, more so on Tarett and then Smart Racing and so on.

Why are sway bars so expensive? Is it the materials? Low volume, high quality manufacturing? Porsche tax? I'm sure it's a little of all 3, and more, but would like to know what's the main cost driver.

Lastly, what makes the main bar special?

Price is always what the market will stand, rarely anything to do with manufacturing cost. Mind you selling something for a dollar that costs $2 to make is not the best business plan.