thats a pro install ive just completed a full install on my car and well it dont look at all as good as yours as well includeing 8 inch touchscreen although mine is a prefacelift and u cant really mounth the screen as if its stock althought i have found some good frontend software like centrafuse
http://www.fluxmedia.net/ thats what im useing atm in my system and its running on a micro atx with a m2-atx powersupply with an AMD Sempron 2800+ and a gig of ram bolted down ofc and the screen has to sit infront of the two middle vents some usful links if u get around to build a pro pc to go in the car
http://www.fluxmedia.net/http://www.linitx.com/ they sell all the pc side as well as touch screen but i sourced mine from ebay for 112 quid and
http://www.digitalcar.co.uk/ they will help with all the niggles u have with it
i wish i had a facelift now with a double din
keep up the work and keep us informed
M2-ATX - 160W Intelligent Car PSU £58.46
http://cgi.ebay.co.uk/GPS-Receiver-Sat-Nav-Laptop-PPC-PDA-USB-Car-Yacht-DIY_W0QQitemZ300125662657QQihZ020QQcategoryZ75327QQrdZ1QQcmdZViewItem#ebayphotohosting thats the gps reciever 19 quid no matter where i go whether it be peak district i always get over 8 satalites and the antena is sat in my rear screen
screen £112
and then about £20 on fuse holders and misc the amp i already had a 4 channel amp and it came in really handy
so 200 quid on my install as i already had most of it lieing around the only problem i can see is the hard drive failing as its not a laptop sata

on mine but you wont have that problem hope ive helped u with links and everything