You can determine whether it will work by using this: FAQ: Will <insert PSU model> Power Supply work with my system?
There's a link to CPU electrical specs, where you can determine the max power draw against the availabel 12v power for various DC-DC power supplies.
GPS isn't a PCI card. It's most commonly a USB device.
Also, the power draw for your optical drive is probably for a full-size drive, not a slim laptop drive, so expect a slim drive to draw less power (and only from the 5v rail!).
I believe the M2-ATX would be just fine for your project.