Z3's have definitely hit the bottom of their depreciation curve. Are they likely to go up in value I think probably yes they will if the general trend of car values continues. They are little sports cars with big naturally aspirated engines which quite frankly will be a thing of the past (if not already). But eight grand is absolutely bonkers if you ask me. I've been looking since February with a very limited budget to get a 2.8 and I've managed to pick up a 3.0 with all the trimmings for a quarter of that price and if you can still do that I can't see how that vehicle no matter the mileage can command that sort of premium. Five grand sounds much more reasonable to me.