I am mostly disappointed in the sound quality of the 10-speaker Sony speakers. The system sounds pretty good at the dealer, but in listening to a variety of music there is some really ragged dips and peaks in the response. The imaging is also really bad, a song like the Posies "Suddenly Mary" with its pulsing shimmering image that was quite enjoyable with the Focal speakers I installed in my previous Mazda 3, is almost completely flattened. I am going to try disconnecting the center channel to start with, but I think the door speakers are probably going to have to be replaced as well, and there needs to be some braces and acoustic mat added to the door panels to get rid of some annoying resonances in the doors.
I think I will just use some masking tape to cover the grille for the center speaker to do an easily removed experiment. If it sounds better, I will then disable it.
The problem is that the head unit will still be sending sound to the drivers as if there is a center channel so the equalization may be way off. I wish Microsoft / Ford would give us more control of the MyTouch system so we could change things like this.