Thank you, GTAHVIT, for this video. I just did this install over the weekend and I'm glad I didn't have to tear out the whole headliner.
That said, it's still a royal PITA to do this swap. I folded down the rear seatback and it helped tremendously, for those of you who have yet to do this. Also, I found it a bit easier to pull down the headliner once I removed my b-pillar trim.
...I'm still sore from contorting my 6'2'' frame around in the back seat, but my antenna looks great!