You'll be glad you ordered / fitted Acoustipack dave - I used an entire 'ultimate pack' kit in my corsair 600D and it made a world of difference... its a nightmare to get in tight spaces though as its VERY sticky on the back and bonds tightly almost immediately - to the point you'll have to rip it to get it off if you dont corrent a 'mis-stick' straight away.
I only wish Id bought a pack of blocks to fill the unused 5.25" bays - something Im going to do soon. Defo better than the paxmate stuff rest assured!