Sean, I would suggest keeping it original. There are many Coupes which have been modified, but VERY FEW that are original. My 73 CS has just over 28,000 miles on it, and the only thing I have changed is to upgrade the ignition, and change the front sway bar to one from a CSL. If you have observed over 130 mph in a 28 year old auto, keep it that way, and enjoy not shifting! All the best, and good luck in what ever you decide to do.