If the torx bolts are just spinning, then they may need to be drilled.
Here is a photo of the box removed:
Removing wet box
I believe there are four torx bolts holding the wet box onto the factory roof rack?
The torx bolts that are held in the roof and roof rack utilize very cheap fasteners referred to as "revnuts" that are pressed into the thin roof sheet metal.
When Nissan installs them the assemblers use a thread locking compound similar to blue Loc-tite. If too much force is applied, the revnut spins in the roof/roof rack metal.
One way to loosen them is to actually heat the torx bolt, and gently turn the bolt both clockwise and counter-clockwise until they extract.
Removing wet box
We used a 250W soldering iron and about 2-3 minutes of heat on each torx bolt.
This can be very patience trying, but it has worked in the past.
Roof rack torx bolts removed:
Removing wet box