Many people have mentioned the improved sound stage when disconnecting the center speaker in the focus. From personal experience, I can tell you it results in much more distinguished left and rights, and a less muddy sound up front.
What you'll need:
Flathead Screwdriver (Optional - If you don't want to risk cutting yourself)
Some tape (Scotch)
I recommend using either your fingers (being extremely careful not to cut yourself) or a flathead screwdriver with tape around the end to prevent damage to your dash. With whatever you chose, very lightly pull up on a corner until it's high enough to slide a penny under the edge. Repeat until you have 3-4 edges held up by pennies, then evenly pull the speaker out of the slot.
Don't pull too hard. The wire connecting the speaker is very short and there isn't any leeway.
You'll see the connector at the end of the wire. Again, the cable is short, so maneuvering your hand in to pull the little tab out and pull the wire out of the connection will be tricky. Big hands, good luck.
You'll see the little recessed tab on the right of the connector, that;s what you need to pull out to release the lock.
At this point, use some scotch tape to tape the now loose connector to the inside of the slot, this will prevent inevitable vibrating and/or loss of the cable (though I'm pretty sure that can't happen).
Now you can lightly and evenly re-insert the speaker into the slot. You'd never know it was even removed.
Spoke to my dealer today, they had no concerns about this mod what-so-ever.