Hi Munro
Here is a picture of the sub mounted underneath the seat, as you can see I have had to mount it fairly far forward due to the step in the floor pan.
Sub Under Seat.JPG
I routed the wiring through the rear panel as shown; If you remove the trim running along the sill, you will find a channel that runs from the rear of the car to the front which allows you to run all of the necessary cables into the passenger kick panel and then into the dash. I used a SOT 908 to connect to the rear speakers as I installed a bluetooth kit at the same time. This is really easy and means you don't have to cut into the original loom.
Sub Wiring.JPG
Here is a picture of the main power cable leaving the interior of the car toward the engine bay. This is a little tricky due to the confined space.
The easiest way to do this is to get a a long philips screwdriver and push a hole through from the engine bay to the inside of the car. Then take an empty BIC biro pen (the tube) and with the help of a friend, use this tube to push the screwdriver out. This will leave the tube poking through the rubber grommet. Next feed the wire through the tube and hey presto your done

Remove the tube from the wire by crushing it to peices with a pair of pliers.
Loom Inside.JPG
Run the cable to the battery and make sure you put a 10amp fuse in the line. The ignition feed for the amp can be taken from the cigarette lighter.
Loom Outside.JPG
I hope this helps and if you need to kow anything else just let me know
