Without knowing what car you have, and what size the rear speakers are... I'd recommend these...
http://www.caraudiodirect.co.uk/product_info.php?products_id=2985
You don't want to spend loads on rear speakers. Save it for the fronts. Also, 6x9's on the parcel shelf are a great way to entice a thief. You want to keep things stealthy and hidden away.
It's also more suprising when people get in the car and can't see any big flash speakers on show.
http://www.caraudiodirect.co.uk/product_info.php?products_id=2985
You don't want to spend loads on rear speakers. Save it for the fronts. Also, 6x9's on the parcel shelf are a great way to entice a thief. You want to keep things stealthy and hidden away.
It's also more suprising when people get in the car and can't see any big flash speakers on show.