One more thought on getting your seat and headrest adjusted right....since I am 6'1+" the seat in my '05 GT is all the way back, then I raised the seat a bit, tilted it back and adjusted the back until I got a better angle for drivnig comfortably, shifting, etc. It is not totally optimal, but now is much more comfortable overall. It would be good if Ford added a telescopic feature to the steering wheel. I will probably add a different shifter (tri-ax type) to move the stick a little further back. If I do that, may look into a custon shifter extension for it. About 2" further back would probably do.....
Very few cars these days with a stick are optimal for tall people, except ones that are more than I care to pay right now. I have sat and driven several of the new sports cars out there like the 350Z, G35 Coupe, Boxter, RX8, etc... but none were as comfortable as the Mustang as to leg room. Sat in a BMW 850csi once.....perfect seating and shifting position....$85K too! The new 6 is similar to the 8......still way too much! But I like the American Muscle Cars best! If I ever get one of the 6's I will put a bumper sticker on it "My Other Car Is A Mustang"....that would get some raised eyebrows.....lol
Ok, I degress....try playing around with the seat height, angle, etc....maybe you will find a good compromise. Funny thing...When I first looked at the new Mustang, I thought the head rest looked like it was way too forward, I then sat down and adjusted the seat back a bit. Felt great for me....
Good luck!