it doesnt as far as I know, you would need to tap into the rear speakers to get access to the feed from the head unit and send it to the amp via some rca wire adapter.
I was considering this myself, but a new aftermarket head unit it a lot better.
The Team Integra community is a forum dedicated to Acura Integra enthusiasts to discuss engine building, suspension, repair, detailing and anything else Integra related.