VR/VS are most common to transplant into earlier models.
I am actually attempting a VS fit to a VK this weekend. I nutted it out with a couple of mates. Don't make the mistake I did and buy the mounts that go into a VS, they are too high for the VK door trim and the cover wont sit down. You can buy a pair of shorter brackets from any auto shop for about $20. I scored both of the VS covers with the map pockets for only $30 second hand. Holden have stopped making them (I went there first). They are only $60 each new so dont get ripped off.
Kain
In the kick panels, that's exactly what i did. Works well, i think the sound isn't as good as it'd be if it were in the door, but hey, i'm not that fussy anyway.