Why so expensive ah? In the states, this headers are called ebay headers where they basically copied SS headers using stainless steel and sell them on ebay (hence, ebay headers). Its started by Taiwan exporters but since the US garages started making their own now, lowering the price, the Taiwan seller are just basiccaly outpriced.
The quality of these ebay headers is sooooooo much better and soooo much cheaper too. They selling em for peanuts there, something like USD50 and you get gaskets with it too.
Where the hell is the seller 2k price comes from? Bit of Stainless steel tubings? Some solder? or "R&D" that they have done to build one from scratch.