I have fitted the MX644D to my 14xx along with a 330muf cap and an Ice Dual 28x18x7 mm speaker supplied by YouChoos. I reckon that you would get an 8mm speaker in attached with BlackTack or a 9mm if you use double sided tape. Not sure if you would get much more in in the way of stay alive.
Can put up a couple more pics if required.
Nick