Just bought a used 2005 Boxster S (987.1) and I can't identify two black boxes in the frunk.
One's in the upper compartment near where the CD changer would be if it had one.
And one's in the lower compartment behind the toolkit and tire inflator. It's clearly an audio amplifier, but I don't know if it's the factory original or if a previous owner has replaced it with something else. (This car has Bose speakers, the standard CDR-24 radio, and no PCM/GPS/screen.)