The simple/short answer is if you buy a Nav CD up to and including 2006 it is basically what you are used to already except with updated maps. You can't add/edit destinations while moving unless you use the temporary/manual override (top left, bottom left 3 times). From 2007 and up they removed that manual override so you can't add/edit destinations while moving and there's no way to manually override.
See here
Lexus Navigation Controversy and
Toyota Navigation - a little over the top if you ask me, but it has more information on the topic.
There are at least 3 other options I know of and this is where it gets dicey:
1) there's a "bypass" procedure where you snip wires to bypass the vehicle speed sensors.
2) there's a loading.kwi file where if i understand correctly people take the loading.kwi file from earlier versions of gps and burn their own cd that uses that with the new dvd software. I've heard of people having problems with the burned dvd's being different thickness and getting stuck in their nav ecu.
3) coastaletech.com sells lockpick software that depending on the version you buy will enable more functionality while moving.
See below for more detail on bypass procedure and coastaletech.
Regarding the bypass procedure, you permanently trick the nav display into thinking the car is not moving. It's described in numerous places. However, the way it's typically described it only allows you to watch DVDs while moving, it does not allow you to use the nav while moving. See here for a nifty solution to that problem:
NavigationBypass.com - How to Override Navigation and Bypass Navigation Lockouts, Navigation Bypass Procedures for Pioneer, Lexus, Infiniti, Nissan, Toyota, Cadillac,
To summarize - there is a vehicle speed sensor on both the nav display and the nav ecu. Fooling the nav display only allows you to watch dvds while moving. You would need to fool the vss on the nav ecu to use the nav/bluetooth while moving. The problem with that approach is that the nav relies not only on gps signal but also on data from the car's movement. If the nav ecu thinks the car isn't moving your nav isn't quite as accurate (I guess it only takes readings periodically and relies on movement data to fill in the blanks?). So the site above describes using a switch to temporarily disable the nav ecu's vss so you can use the nav and then switch right back to moving so it works smoothly.
Regarding coastaletech's solution, they sell the lockpick software which supposedly unlocks all the capabilities even for 2007+. I see contradictory info on their site -
APPLICATION GUIDE says Ultimate Lockpick 3 doesn't work for vehicles with dvd or rear entertainment, but
LOCKPICK 3 implies it does work for any 2007+ navs... Anyone use it on 2007+ that can vouch for it?
