With the doors gone and the windows out of a soft top, you are essentially creating your very own home made parachute. The top will catch more air than a skateboard at the X games. It will flap in the breeze, and put some severe stress on the 2 back corners like a C cup bra trying to hold up a pair of double D's . Yeah I'm a smartass!
Sure it will give you more protection than a bikini top, but a bikini is designed just like a womans bikini top, to just cover the important stuff.
Take your windows out and the top of your doors off, and take it for a ride, you will understand 2 things, it wasnt meant to be used like that, and or, the stereo amp needs to be much larger to drown out the noise that the top makes flapping in the wind.