Any radio that is the same physical size will fit make sure you have the unlock code
This was in another thread:
The 5000, 6000 & standard 7000 as well as "round cornered" 6006 units should fit and the 5000, 6000 and std 7000 still have the CD Changer connection. As stated by others, you'll lose the rear controls but that stops the kids changing the track or station, so it's no bad thing!!