I'm looking to setup a laptop based CarPC in my new-to-me '06 Corolla. I plan on mounting the laptop inside the spare tire compartment of the trunk. One thing I've been concerned about is which power supply I should be looking to get? In my research on the forums thus far it seems the CNX-2140 is pretty much the bread and butter of the scene. However I'm only looking to run a 7" lilliput (any suggestions on which one?) and the Pentium M based laptop (Latitude D510).

All I really want from this setup is to be able to play songs off a USB connected portable HDD, (which I plan to connect in the glove box), and reliable GPS navigation via USB GPS dongle. The thing that pushes me towards the 2140 is that it is able to interface with the laptop via USB triggering shutdown. I have also heard it's easier to reprogram/update the firmware. Is the shutdown/startup something that's easily achievable with a software based solution using the 1900?

If the 1900 isn't underpowered for my setup (monitor, laptop with 2-3 usb devices connected) and a reasonable shutdown/startup can be implemented then perhaps I can save ~$35 and not have to wait for the stock to replenish.

As an aside, here's some threads which have kind of helped me visualize my goal:
2007 Black Corolla S - Mini PC (Complete!)
2006 corolla s oem install