I have no clue if this seller is legit or if the product is good quality, but here 'tis.
Nissan Spoilers - Nissan Car Spoiler 370Z, Altima, Cube, Maxima, Versa
-balistic, I'm not sure what the issues are with removing the factory spoiler, but I was thinking that using a small plastic body panel tool to slowly work your way around the spoiler might help. Just a wild shot in the dark.