For those that have a Mustang convertible (I have a 07 GT converible) - if you have some squeaking or clattering from the body sway, just take some vaseline and rub it down the the somewhat hard plastic where the front windows meet the back windows, and the clattering goes away.
My previous Sebring convertible was the same way although the plastic running up the edge of the back windows was more rubbery than the Mustang's and didn't seem to require lubing as much.
And I didn't thing I had much use for vaseline any more :)
Toad