I have sold something once on here and sold it for more then half price and it was brand new unused. But I did it to help someone out sense I did not need it anymore.
And on the headers I ceramtic coated mine for 25$ and works great. But OP lower the price and provide free shipping if your still going to sell for a lot.
They do look like they had a real good job on the coating and someone will buy so good luck with the sale.