It's actually not that bad once you get into it - I had to remove it to put in my rear speakers (I should have deadened the car then!!!).
From
NissanEnthusiast:
Before you remove the deck you have to remove the rear pillars. pop out the "SRS airbag" rectangular piece with a flat head and remove the 10mm bolt. Then use a flat head wrapped in a wrag and start near the front of the car and pry off the A-pillar. I used short hard jerks to pop it out and slowly moved back towards the rear window. Then you can lower the rear seats. You'll see a plastic trim piece where the seats would rest if they were up... it has I think 6 pop in plastic taps, remove those, and then remove that piece. Remove the round circle ring that surrounds the seat release button (one with the key hole in it). Pop off the rear tail lamp (it just snaps in place) remove the harness for it. Then the hole rear lid just has white plastic plugs holding it in. You can see them from underneath the rear deck. Pop off the rear deck lid. Install in reverse order, deck first, then pillars.