If you're happy with a slim-line single channel camera, have a look at the
S.WILL dash cameras. I did a lot of research on dashcams it was definitely worth it.
I've got mine hooked into a dual battery system so it's constantly recording, but they come shipped with a standard 12v lighter plug so it's easy to install on standard vehicle. The image quality you get from them is second to none. Full HD, good wide angle (easy to read license tags), GPS overlay, good software etc.