Yes, you can replace the factory radio with an aftermarket with no problem. Metra has a subcompany called Axxess. These are digital interfaces that allow you to remove your factory radio without messing up your 2000 and up Bonneville'* computer. If you have OnStar, you'll need the GMOS-05. If you don't have OnStar, you'll need the GMRC-04. I called Metra and the only place that sells these adapters in Lafayette Radio: http://www.lafayetteradio.com/
. The folks there are real friendly and helpful. I just got the GMRC-04 for my 2000 Bonnie and it works great. So, that should solve that problem. As far as cutting your dash, if you work it right, you won't need to. Trust me.