You can add the Bose system to any 986, it was an option but is also an aftermarket kit. So it could have been added by a previous owner.
Where can I find the aftermarket BOSE kit that you speak of?
__________________
-99' Zenith Blue 5-spd...didn't agree with a center divider on the freeway
-01' S Orient Red Metallic 6-spd...money pit...sold to buy a house
I saw the kit a while back. It was a link in a forum post either on here or renntech. I don't have the link though.
Are you sure it wasn't the OEM rear speaker kit or just someone selling the BOSE subwoofer?
__________________
-99' Zenith Blue 5-spd...didn't agree with a center divider on the freeway
-01' S Orient Red Metallic 6-spd...money pit...sold to buy a house