I think you guys are missing the point here. It says that the car was designed to be a prototype, which is always way, way, way more expensive than the cars built after it. I am sure the kits would have sold for a few grand like other kits which people could stick on their camaro's, or a turn key car could be had for $20K + donor car, just like many other kit cars.
I don't think a Viper is a great kit car as the value of a viper isn't as high as a Ferrari or Lamborghini or one of the other typical kit cars. If you spend $10K on a Camaro and $20K on a the turnkey portion of it, you could have gone out and purchase an early Gen I viper just about.