for me the perfect Mustang was the 1966 GT 350 which I bought brand new,sorry to say I sold it many years ago
Wow, you were one of the very few to have owned one of those true classics and you bought it brand new. I still remember many years ago walking down a street near home when something caught my ear. I turned around and a white with blue stripes GT 350 drove past me. What a sound that early 289 made with tube headers and solid lifters. That was one of those days that made me a fanboy.
Somebody already suggested this but maybe Ford should have set the Mustang aside similar to the Corvette and 911s of the world and just produced a new "world" sports car. Just a thought but I'm sure the accountants would not be in favor.