Funny you bring up this thread. I actually just finished adding a NAV unit about 2 hours ago. I have a 2011 Laredo X that came with the 430 - no NAV (RBZ).
I bought the following 430N (RHB) on ebay:
I got the unit and was disappointed that the bracket was totally different (screws were on the side instead of top and bottom). However, I hooked it up to see if it would work and it worked perfectly. So I then performed about 30 minutes of frightening open heart surgery, dismantling my existing 430 unit and the 430N unit.
I pretty much swapped out the entire front section of the radios so that my 430 screen that is tied to the correct bracket is now connected to the 430N unit.
Once that was done I installed the franken-unit back in the Jeep and all works like a champ! As long as you get a 2011 MyGig with the High Speed Bus you'll be OK.... hopefully the one you get has the correct bracket so you dont have to do what I did.
If you look carefully, you can see the RBZ on the bottom right hand corner of the radio:
Also, its easy as hell to take off the front dash piece that surrounds the radio. Others on the forum were saying to use a putty knife or something to carefully get in between the the cracks to pry it out... you dont have to do that. The little storage compartment under the AC controls, open the door so you have access, then put your hands above the door while it is opened and you can just pull out on the entire dash piece and it'll pop out. Took me 30 seconds to get it off.