I remember the art cars from Warhol and Stella from back in the day though I don't think they cost as much then as they do now. In fact, I think they cost just a little more than your standard Minichamps and/or Kyosho if memory serves me right. And IIRC, the art cars back then did not come in a nice base with a matching acrylic case, art book, etc, but I could be wrong.

Looking at eBay's sold items, it looks like there were a bunch of BINs that sold, and Replicarz's auction item sold for $490 plus shipping. I think that is cheaper than what a Spanish diecast retailer told me (EUR 500+) which I once thought still had it in stock.

Interestingly enough, I made an offer on a car that was being sold by a collector in Indonesia. As my initial offer was way lower than the BIN price, it automatically got declined by eBay. I left it alone for a few days then I was all of a sudden contacted by the seller to make me an offer. It was still way higher than what I wanted to pay, and gave him the two example auctions above as to what I think the current market value of the model is. A few email exchanges later and we agreed on a price. It was still more than what I wanted to spend but it at least included shipping, which, for an item like this can be expensive especially it is coming from the other side of the world (I am in Northern California.) I really wanted the car for my collection since I own a 1:1 E92 coupe, not so much as an investment. Only time will tell though if these will continue climbing up in price, it will be interesting to watch.