amp

I fitted a Kenwood amp in the boot, and ran the wires along the trim by the carpet on the drivers side. I also cut-out and fitted some Kenwood 6X9 speakers into the parcel shelf. This all runs off a pretty standard JVC headunit

click here for the > parcelshelf / speakers < page
I screwed the amp to the seatback (you need to drill pilot holes first, in order to get the screws into it - its quite tough). I should have fixed it a couple of centimetres further down though, as it nearly catches on the parcelshelf (see last pic)
After removing the trim form the drivers side, this is what you see
Drill a hole
close-up
And make sure you add a grommet to prevent the body chaffing through and creating a 'short' to earth
run the power lead from the battery through,
like this
and add the small 'control' wire (thin blue) from the headunit, that tells the amp when to power-up
add conduit from VWP to protect the cables on the curve, and finish with tape to hold in place.
I used this rear seatbelt bolt to affix my amp earth cable
like this
after drilling another couple of holes & adding grommets, you can feed all wires through into the boot area
and they will hang like so :)
This pic shows them connected up with an extra fuse in place. Note, this is not the correct place for a fuse - it should be at the other end of the wire near the battery. I have one there too.