Yep, and lower power consumption is also pretty important, if I am not mistaken, that adapter probably supplies 19V, so you should be able to use a DC-DC power supply. It is definitely not the best setup (I personally wouldn't use this for a CarPC, but it's a cheap start. I would still rather go with a mini-itx solution), but it works. It does show how little power these machines use, yet they can be so powerful.
It does look like the CDRW drive is just a laptop drive, so if that's the case, you should be able to replace it with a laptop DVD-ROM drive.