Hello I am in the market for a 2011 shelby gt500. I have found a used one with 4500 miles with the svt performance package and navigaton that I can purchase for 42,000. Is this a good deal or is this generally common wth the mileage listed? I know the 2010s have greatly depreciated due to 2011 improvements however I didn't know how the used market was for the 2011 shelby gt500. Any purchase advise would be helpful from those that have recently bought new or gently used 2011 shelbys.