The "personality" that is transffered comes from the BRAIN! All of our information, personality, memory, likes, dislikes, EVERYTHING is in our brain. Transfer that to a new body, and you keep everything but the body.
It is, in theory, possible. Right now? Hell NO! I sort of wish though.... I want a cool cyborg arm!!!!!
Anyways, the idea of how this works (and they have tested it, some of it will work with some tweaks): Nerve impulses from the brain control movement. These come from synapses fired in the brain, which sends the signals into the nervous system, down to the spine, and into the body. This is why when you break your spine(al cord) you are paralyzed. The idea is to hook into these impulses. Say your arm has to be amputated due to cancer or such. So now your arm is gone. Well, after they take it off, they put on a metal plate on the end, to do two things: cover the stump, and hold sockets. These sockets are attached to your nerves, and will plug into the new "arm". Then in the arm, the electrical pulses are deciphered, then transferred, encoded again, and sent to the mechanics in the digits/arm/wrist to move it.
While a whole cyborg body seems ridiculous, it might be entirely possible. In addition to above experaments, doctors have been testing a chip that is emplanted into the brain. So far, a paralyzed man can work a computer with it. Impressive, but very much in the toddler stage, if even that.
As for people being implanted in cyborg bodies, eh..... I don't know. Maybe. But it may not be something everyone would want.
The firewall part is just stupid. Cracking a firewall is like what H2SO4 said. I would watch that though.... LOL.