...if i were to choose an LCD screen for the NAV pocket... would the car/pocket have to be cut/modified? or could a screen fit right in there some how and can be put back to stock with ease?

What screen fits perfect there?

 

If you have an 03 the only thing you have to do is take out the screws for the cubby box from the back and a Farenheit 7001 or 7000 fits in there perfectly. If you have on 04 you will need to buy a 03 cubby box/lid combo and do the same.
Do a search there are a million threads on this subject.