Yeah it's the six speed. General rule of thumb when i shift it for economy i keep the rpm below 2k. Anything over that the mileage goes down. We've been wanting a programmer for it but haven't been able to scrap up the money due to medical bills.
So far all we have done is stick in some flowmasters. Love the car! It was a steal cause it was slightly used (under 2500 miles). I would one day like to have a turbo stuffed under the hood. Have you seen any of the videos of the new gen mustangs with a "loping idle" tune? Sounds pretty awesome but not sure what it does performance wise.