I have only switched the unit in my P5, but removing your Kenwood should be really easy (I replaced my stock deck with a Kenwood, and removal of my Kenwood is a snap - no reason to think yours is different).
Either go to a local stereo shop and get the Kenwood removal tools (these are supplied with every aftermarket Kenwood - if the shop won't just give you a pair, take a walk - they are cheap metal strips, they should have a ton of them, and shouldn't try to charge you for them - try to talk to an INSTALLER), or you can try a butter knife or similar long flat metal piece. Just try to get the thinnest knife you can - it needs to go into a tight space.
Pry the trim piece off of the radio - just the skinny radio surround, not the whole silvery trim of the center console. It should pop off easy. Now take your removal tools (whatever they are
) and stick one in each side of the deck, between the deck itself and the metal mounting sleeve. Push the "tools" all the way in, and they will release the locking tab on either side. Pull the tools and the radio out all at the same time - easy as pie. I would suggest getting the proper Kenwood tools, as it will make this process a bit easier - they are really thin, and fit in with almost no force, and getting them should be free.
I believe all Kenwood units use the same wiring harness, so if you replace your deck with another Kenwood, you probably won't have to cut any wires - just leave the existing harness and plug it into the new deck. Also, all the mounting sleeves are the same, too - so buying another Kenwood is a really good idea for your installation - pop the old one out, plug in the new one and slide it in until you hear a "click" and you are done.
I know the Kenwoods you are looking at, too - they're really nice - motorized face, D-Mask + detatchable face, cool graphics, 3 sets of pre-outs, yadda, yadda. I'm considering one myself to replace my MP8017.
Good luck - you should have no problems popping the old deck out.