Without reading much information, just by looking at the pictures I'm estimating it's a 1inch spacer. This raises the front roll center by a little over 2 inches and significantly improves the camber curve. It's pretty expensive (and would be expensive to replace) and those running wheels smaller than 15's might have a problem.
Well they are on yahoo auctions japan... i cant work out the brand from that add but i have looked up the moonface and ikeya formula roll centre adjusters before from other sources and they are usually around $350-400. So this price isnt unusual if it is infact a brand name japanese part. Genuine jap performance parts arent cheap incase you havent noticed, but quality is unmatched.
In saying that though like on ebay you gotta be careful with yahoo auctions as to what brand things actually are.