Metra Products: 2006 Pontiac Grand Prix Model Number
Speaker Adapter Harness 72-4567
Speaker Accessory N/A
Speaker Front Location 1 door
Speaker Front Size 1 6.5
Speaker Front Location 2
Speaker Front Size 2
Speaker Rear Location 1 rear deck
Speaker Rear Size 1 6x9
Speaker Rear Location 2
Speaker Rear Size 2
Speaker Other

this should help