I don't think you understand something called supply and demand. The vf39 is a dime-a-dozen turbo. People buy and sell them for $300-$400 every day. Eventhough it only has 100 miles on it, it's still only a vf39. It's a stock turbo, nothing special about it. It's not rare by any means and is only a minimal upgrade for a WRX. You may think it's worth $800 but you're going to sit on it for a long time if you expect to get that much for it. It came with your car anyway so it's not like you paid $1,000 for it. Whatever the going rate is for a vf39 is how much you should ask for it. You may be able to ask a little more since it supposedly only has 100 miles on it, but nowhere near $800. Good luck with the sale.