[sean2]

I've always owned 10-20year old cars, and frequently replacement parts aren't available; I have to find them on ebay or craigslist and I've no way to know weather these were scavenged legally or stolen.

I've also used Craigslist because new parts can be 5 times more expensive than used parts. You may buy all your items new, but most of the working class people on my block, who are constantly upgrading their cars, probably can't afford it. So, I have no problem imagining a large black market.