You do realize that the OEM system requires several parts? Different buttons on the steering wheel, different rear view mirror, dvd reader and hardware that mounts in the trunk, head unit, and GPS antenna. Also, in addition to the wiring that will be missing, several other wiring changes have to be made too. It's a lot of trouble and expense, when the after-market units are mostly better anyway. I have an 06 with factory nav. It's not great, but okay. I am putting a Pioneer in my 04. It's much easier to install, and does way more. (It has a few down sides too.)