I'm in the minority here...but I would trade in my modified 2011 Mustang GT for an immaculate, SUPER low miles 2007-09 Shelby GT500.
The purchase/trade would not be based on performance/comfort/technology...it would be for the eternal "cool" factor that comes with the Shelby badge.
Imagine your fixed up, 2011 Black Beauty parked next to a shiny 2009 Shelby GT500 at a car show or any parking lot. 10 out of 10 times, the crowd or onlooker will gravitate to the Shelby GT500 and wished that they owned one. They'll say that your car is "cool", but the Shelby parked next to you is "way, waayyyy cooler"...it's a RESPECT thing...You would belong to an exclusive club!!!
Plus, I would definitely modify the GT500!!! lol
Something like this: