kyo, hope your listening still
with the stock stereo which stereo are you trying to take out? is it the mazda one, or the kenwood stereo??
if the mazda stereo, you officially need the official ford removal tool, which officially only mazda and ford dealers have...
in reality just get a wire coat hangerand cut into two pieces rougly a foot long each, then making sure that sharp edges are smoothed over, you need to open the side covers on your stero with a small screwdriver.... this will reveal two holes, place the new tool into the holes (making sure that your tools egdes come to a perfect U shape...
once in it will take a little whiole to wiggle around and find the right spot... eventually you will feel a click... then by pushing inwards from BOTH sides thie should release the clips and the stereo should come all the way out of its hole....
if your installing any aftermarket stereo i would reccommend two things... if available, take off the front panel (on car) and screw into the provided holes... this makes for a slightly more secure install.... second of all use an aftermarket adapter kit... even if only to bare wires... the mazda wires are ok, but whatever you do, don't cut them!!! they are thin as!! that and if they detach, you will certainly be screwied in finding a better acc wire than the original!!!
good luck