Like these?
If you get them you need to glue the inner part of the enclosure to the outer part as it vibrates with high bass, I used a hot glue gun - worked a treat.
Nick
How have you ran the speaker wire through the door, different to Danny_California?
I ran the wire following the existing central locking wire that the alarm company installed.
It travels down the void in between the door and pillar, grommets top and bottom and siliconed in for good measure.