http://www.sonicelectronix.com/cart.php?vehicle_year=2003&vehicle_make=CHEVROLET&vehicle_model=IMPALA&action=view_car_specific_accessories&cart_item_id=12652351&get_accessories=View+Accessories
seems like this is all u need
its an old alarm from like 2000 it says united states alarm systems something like that i cant remember i think i might just pass on this alarm and get a cheap on from sonic ...so my guess the locks would be on channel 1 and 2 right?