As a tidbit, I was in the viper market for about 6 months and did a lot of due diligence with posting here, watching numerous different forums and was close to buying one from here. I decided to check out a car that is mint condition, red with silver stripes, all original and no mods (bone stock) and the initial price went from 50k to 40k to 37k and I decided to wait. 3 months later, the car is still for sale. THe car will probably sell for about 33k and it will probably be sitting in my garage. I did a LOT of research and I think that if you can deal with taking off about 5k, your car will sell within 2 months. It will be very hard otherwise. There was a 97 viper GTS on autotrader for about 6 months with the following mods: Belanger headers, borla exhaust, smooth tubes, k and n filters, 2008 HIDS with 7600 miles. THe car was LISTED at 37,900. I don't know what the car sold for but it took about 6 months. I talked to the guy selling and he would take 36k. My guess is the car sold for less.
Two points.
1. Using your reasoning you might as well wait a year, two years or ten years. MAYBE the prices will go even lower. But at what point do you actually want to get IN the car? You can wait forever. It's like buying a new computer, there's always something better down the road. Sometimes that road never ends. Wait another five years, why not?
2. Regarding that Autotrader ad, who knows the history of that car? Maybe it a little "story" that lowered the value, maybe not. But using a random car plucked off an ad is hardly indicative of the market as a whole. It's like Ebay, 3/4 of the cars on their have some lil story that's not explained.