Install myself -- yes, with some help from someone who had before. For the LOC itself, if you're only adding a sub, you just have to tap the wires into the pair you want the sub output coming from (likely the front) Just a standard wire tap will work fine. IF powering speakers in addition to the sub, you need to cut the wires and route them from the head to the LOC, then from the amp back to the speakers.
Power from the battery -- yes, ANY amp or seperate sub will require a direct power line + a remote power line. The LOC itself doesn't require power, but any amp you use it with will.
Removal for install -- center console, stero console and driver's seat, all are easy to remove. Center console is a few 'pop outs' and four screws, the driver's seat is 4 14mm bolts. Stereo console is two screws for the cupholder, pop off the plate, and 6 screws for the head unit. I also had to remove the rear seat to run wires to my sub in the rear, but that's easy also (6 12mm bolts)
Obviously my amps are under the driver's seat. Installation elsewhere may require more.