It's funny when people argue 10ths of seconds and a couple miles per hour when everyone who has been to a track knows that the driver makes a much bigger difference, and even with the same driver the better tires are going to make the difference. The Viper is a much better sorted track car, but it wasn't in '97.
As for the original question, imagine if you could get a no stories car for 150k or a salvage car for 100k. What if you could put that extra 50k in some other investment? Or as the guy said, he can't get the no stories car and since their value goes up every day, this may be the chance. If the GT guys say it's good, jump on it. Certainly not going to lose money.