Comparing the two is like asking which child do you like the best. Each one has it's strengths. I bought all my cars new and then hold on to them so the "need" for the garage. The Shelby is my daily driver with about 18,000 miles. It is an 07. The supercharger is it's strength and it has the tremec transmission like the two Vipers. The Boss unfortunately has the getrag transmission which I don't like near as much. The Boss is a Laguna Seca version and has a lower rear end ratio that makes it seem quicker than the Shelby even though it's giving up 56 horsepower to the Shelby. The bottom line is I once feared technology but it has become the hot rodder's friend and because of technology the Boss is more fun to drive because it seems lighter. I hope this kind of answers your question.