Mine's a CLK230K 2000 facelift so the DIN slots are together (plastic spacer between them). I originally went with a command system so I removed the spacer for that, but I had such problems with it power wise (TV harness fault apparently) I abandoned that in favour of a carPC which I thought would give me more flexibility.
The PC is mounted in the boot over the CD changer, I wanted to remove the CD changer and put in in there, but it's slightly too big. I'm using a ChyangFun Cellbox for the PC, it's an AMD XP2000 with 512MB Ram and a 160GB disk. 4x USB2, Firewire, 1 PCI slot and LAN. 6 channel audio.
I ran VGA, 2x USB, 2x 4 way Audio, 1x 2way High quality audio, 1x 7way multicore, 2x PS2 extensions (all 5 meters in length) from the glove compartment to the boot chnager location.
I'm currently using an inverter to power the PC, but I'm changing to an OPUS 150W DC-DC psu with automatic startup and shutdown.
The screen is a 7" widescreen in dash TFT, with a USB touch screen overlay and VGA connections and composite video. It was from DigitalWW for about $530.
I've housed an IR receiver and Keyboard receiver under the ashtray cover, I intended to put a slimline DVD in there as well, but I didn't realise how the cover worked ,so I don't think there is room now, I will locate one in the Glove compartment along with some USB 1.1 & 2.0 ports. There are 2 USB hubs behind the glove compartment as well. A 4 port USB 1.1 hub and a 4 port USB 2.0 hub. These are for the IR receiver, Touch Screen and DVD rom (USB2 to IDE converter). As well as providing spare ports.
The GPS receiver will be on the back parcel shelf and connect via serial to the PC. I will post some more pics when I've completed the project, I have a cool Merecedes skin now courtesy of another forum member.
Craig