Where does it "lock" into place? On the side pieces that are screwed into place from the dash kit? If so, I can see if I can make it to where I can pull it out if needed. There's things I want to add in later to the car including a sub + amp, and then an amp for my door speakers. So I want to be able to pull it out and redo stuff as I add it in.When I replaced the radio in my 07, it was a permanent install unless you wanted to remove the dash. I drove around for about 6 weeks with the radio almost locked in, but not all the way locked in. I wanted to make sure that everything worked perfectly before pushing it in the final half inch. I believe the 04 will be the same way. Make sure everything works as it should and that you are happy with the radio because once you snap it into place, it is going to take a lot of work to remove it.