That's how I did mine. A lot of people do like to keep the HU though. If they have trouble w/the computer, they can still have music.
I didn't want to do a lot of fabrication, and the spot the factory radio was in was nearly perfect for the Lilliput monitor. And the factory radio sucked anyway, it didn't have any good features that I would miss.
I have been lucky w/my setup being pretty stable. I spent a month or so reading the forums, then started buying the parts I wanted. We installed it over a long weekend, and I've been very happy ever since.