Regarding wholesale car auctions:
1) First, a dealer ties HIS cash up keeping a used car on the lot, new ones are FINANCED, so unless he has a good used Viper business, he will most likely wholesale it out.
2) Some auctions are know for their quality, others for their junk. Occasionally you'll get a deal on a good car if it goes to a "junk" auction, however, don't hold your breath waiting for a Viper.
3) Manheim has a High Line auction twice a month during the warm months. Vipers go thru there, however, I haven't seen their sale prices. The NADA book probably doesn't mean much because they give a broad range of prices which don't really tell you much.
4) Most of the time, a Viper will not go thru in winter because they will take a beating, if they have the car during the winter, they will sit on it until summer or perhaps sell it in FL if they have the connection. Of course, if someone HAS TO SELL during the winter, you will get a deal.
5) Big drawback is that you have to be trolling the auctions to get the deal - you just can't go to an auction and get a deal. You're still stuck with TIME = MONEY problem.
Frankly, I would think that an individual selling a car might still be a good place to start because in some markets, if you're selling a car, you must eat it! Try buying one from Pittsburgh area and you should get a deal IMO.