theirs a gap in behind that that'll go in behind the dash, as far as the headliner goes you could probabilly tuck it in between that and the windshield, but i'd remove the headliner too. If your removing the headliner you should probabilly just wire it into the reading light area like i and a bunch of other people have done.
"If you want a picture of the future, imagine a boot stamping on a human face... forever." -George Orwell