I would pay £350 max for a brand new one I would say around the £250 mark is about right pending it's condition, cast iron still cracks over time just like anything else, the beauty of it is you can have mad quick spool, and you can run bigger turbo's whilst still maintaining the stock heat shield the problem is everyone's going ewg and with life time warranty on manifolds as above it will be hard to get the cash as nobody really buys jdm parts anymore well that's the impression I get.