Remove both inboard tail lights. You'll need a Torx screwdriver, sorry, don't remember the size. I'd disconnect the stoplight themselves so they don't scratch the rear facia while hanging from the wires.
Reach inside and you'll discover 2 nuts holding the spoiler to the body. Remove these and you 'll have enough room to lift the spoiler out of the hole far enough to disconnect the wire. You may have to swap out the light to your new spoiler.
Use care when reinstalling the stoplights. The clips that the screws thread into move easily and are hard to get started.

sure would taste good after this.
