My experience with unusual or older cars is a friendly camaraderie. I've found this is Corvairs, Mustangs, GTO's, XKE's, and certainly Z cars until the advent of the 350Z. My 300 ZX tt was my second Z, and up until then, a wave was almost the rule. The last wave I got months ago was from a 280Z.
Last week I had a 370 driver stare at me as I waved at him and he looked at me like I was crazy, and just slowly drove past, staring.
Oh well life moves on and maybe Z car drivers can have the reputation Porsche drivers get, Pricks on the inside, or Corvette drivers and their small pricks.
If I can, I will continue to wave.
