I've been running a SGT7 for some time now with a dual ganged pot for volume control. However you cannot permanently mount a tablet into your car like you do a carpc or a laptop due to heat. You could however if you remove the battery since its what gets damaged and doesn't allow you do even turn on the device when hot. On my SGT I had a HDMI Media Dock fiberglassed into my stock faceplate, turning it into a dock in my car. Worked awesome till I noticed a crack that I had to repair and I ended up selling things and trying other things and this and that. The SGT is awesome but to get better use out of it and have a funner experience the stock rom must go. However lately they have not fixed the audio output of the hdmi dock on CyanogenMod Releases. They have been working on it but working on other things is a higher priority.
So I decided to try other tablets finding out in my small space I cannot go larger than a SGT or Kindle Fire. Other vehicles could easily run larger tablets. My preference is the Nexus. Its the best tablet around and I wish I could have used it but after trying, there is no way.
I ended up picking up a laptop and a lilliput for cheap so I'm back to the carpc world. BUT installing Android 4.0 on the laptop dual booted with windows. I feel I'll have a better experience this way since I require windows to data log and tune my 600hp sports car.
Tablets are awesome but you can find yourself trying soo much or almost destroying the tablet easily. lol my first attempt at molding a dock resulted in buying a new shell for it after destroying it to get it out of the mold. Then later noticed that the tablet was somewhat odd shaped which prevented me from removing it easily, it wasn't square lol.
I hope all goes well with dual booting Windows 8 and Android ICS.