Shame I dont have pics of the ones ive fitted in cars before but all I did was measure the standard box make that out of mdf but the face of it i'd extend and cut a hole out of it and mount the amp next to it from behind so all wires were hidden.
You should get a general idea from the diagram (sorry, i did it in 5 mins in paint, works only drawring program) it should just fit behind the big mat and back to the seats and between the arches so you could get to your wheel and I always use conector plugs so If you go on holiday say and you need the space you just unplug and take it out. dont worry about screwing it down because the weight and fit will stop it moving too much.
Make sure joints are tight fit and only use mdf sealing it with silicone and filling with car filler. If you spray paint use pva 50/50 mixed with water to seal the spraying surface or the paint will soak in and give an awfull finish and make sure you give it lots of undercoat. v important for there to be no air holes in the sub box. I used 12mm and occationaly 18mm, 18mm is over kill though.
the whole for the sub could go in the top or back facing the seat back or in the side facing the arch, whatever will sound and look best.
I generally spray painted mine to match the colours of my cars but you could carpet it or fiberglass it to make it fancy, up to you. the last one had a second slot cut out for a multichanger aswell.
hope this may help
craig.