I had a 2005 G6 GT. It was a beautiful car, but not what I had expected. The paint was thinning in a spot, and I had some other problems as well. As for the Monsoon system, I had it. It sounded good, but the speakers with the system seemed to have a hard time carrying it. I busted 2 of the speakers and never listened to it with the volume more than half way up. COuld have just been mine, but you never know. No major problems, just a lot of aggravating little problems that took me to the dealership quite a bit. Inside does rattle, especially the dash cracking noises, but you get used to that.
Good Luck in whatever you choose!!
Good Luck in whatever you choose!!