Ok starting from the top
1) The native resoltion is 800x480 but is able to do 1600x1200. I haven't really messed around with resolutions yet, but it's currently on 800x600 using large fonts & icons
2) Yes, it's a widescreen monitor so widescreen resolutions are supported
3) Heat doesn't appear to be a problem, but i havent checked the temperature readings after constant usage. The box although made of thin wood (6mm thick i think), isnt sealed, so heat can escape. It also has a 6cm Input fan and a 6cm output fan, ensuring air flow is good inside.
4) I shouldnt need to use the IP Bus for audio because the output socket on the stereo and input on the head unit are the same, headphone style that you'd find on any traditional PC speaker. I just need a lead to join both together, which i should have plenty of spares from DJ use
5) CPU doesn't seem to be struggling, it's only doing one function at a time and isn't much running in the background, but it's early stages. I haven't fully configured the box and i haven't added all the devices to it, so i'l have to get back to you on that in say a couple of weeks, however you can check it out for real at JAE!
Plans for today are to ignore the PC and try fix my head unit. Once working, i'l set up the audio input / output for the DVD, CD, Sat Nav & MP3 audio!