Talked to the service tech this morning and he gave me a printout as to how to get to the tweeters in the dash. Does not look to be that hard, and you do not have to take half the dash apart. He also told me not to replace the front center speaker as it is for the onstar system and for the notification chimes. Hope this helps.

Thanks for posting that. I've been looking for how to do that. Did he give any details on how to remove the trim cover and garnish molding?

He told me to use a plastic putty knife. I would not use anything metal or sharp as you might scratch the plastic. Both pieces are held in place with clips. Once the trim is removed you will see the tweeters on either side. I would be VERY careful with the tabs that are marked with "2" on page 1, they look very fragile.

Pull up the center defrost piece first. then you can pop the edge of the outer pieces where the tweeters are. They wrap around the end of the dash in the door jamb and have a locator pin on them. I pulled the pieces up to run the wire for the XM antenna I put on the center speaker grill since it's metal and tucked the wire under those dash pieces and dropped it down under the dash on the passenger side where there is a nice opening all the way down. I really like the fastners they use on this car VS GM's normal crap ass "christmas tree" fastners and other hard to remove/easy to break pieces. These appear to be quite sturdy as long as you don't brute force them on or off.