I remember the SD455 Trans Ams were virtually unknown for years, then started kicking up in value around 2006. I sold my 74 SD455 TA in '04 for $19k. Same car would bring $40k to $45k now. When I had my TTA at Mecum, last year, it was the most popular car in the row, but few people knew what it was. Sometimes rarity doesn't equate resale value. Then you think about the GNX....even more rare, but it has always demanded big money. Who knows.