I have never driven the 03-04 cobra but its on my top 5 cars to own someday. I traded my 00 trans am with a friend for a weekend. He had an 04 mustang GT with full exhaust, intake, tune. It was MUCH slower then my fbody but it sounded awesome and i just loved the overall driving experience. I hate fbody interior. its low and long, feels more like a space shuttle then a car. the mustang feels more compact, i imagine that the 03-04 cobra is just going to be better then a GT in everyway...but i could be mistaken