should have two small access holes on either side of the Radio face, which a key goes in each side to pull it out (each key is V shaped, one end of the key in top hole and other in bottom). You can make your own keys as I know someone who did this and they worked.
The wire needs to be coathanger thickness. cut two pieces about 7 inches long, bend both of them into a V shape. Notch all four ends about 3mm from the ends, then round the ends off like a small ball shape.
In answer to your question - before you go and cut all of your wires, it may be possible to buy a "piggyback" wireing loom that adapts the Ford plug to whatever stereo you are installing. It would certainly make the installation easier.
Don't know on that one - Alpine used to make the sound systems for Ford - don't know about the Au's but if I wanted to fit say a Pioneer system to my EF then the Ford plug won't fit. I have seen a conversion loom that plugs into the existing Ford plug which then allows a trouble-free installation.
If one of these is not available for your stereo I guess you don't have any option but to cut the wires.
Have a look at this page, i'm not sure if the AU is the same as the EL but thats all they list upto. They may have it but not have updated their web page yet. I used one of their looms when i fitted my deck...