- The Exec added the length to the legroom for the rear passengers, which was woefully lacking in the short model. It made a huge difference for anyone in the rear seats. I don't recall it adding anything to the legroom for the front people. I'm 6'3" and didn't have a problem with either model. You sit a bit lower than in most planes and your legs extend forward in a sort of tunnel.
I haven't tried sitting in a "vintage" model, but the newer Mooneys allow the pilot's seat to slide back so far that it almost touches the rear seat. Perhaps not true in the older models. More research needed :-)