It's actually pretty easy to remove the head unit. Just use a plastic panel removal tool to remove the side panels on the console.
After you have those off, the HVAC control panel just pops off. Then you remove one screw on each side of the radio and the rest is just clips holding it in. You...
I'm also in the process of installing a subwoofer in my LX, and what I've found is a 1" rubber plug on the driver's side just below the harness that goes to the door. I drilled a 1/4" hole in it and wrapped about an 8" section of the power cable in duct tape just so it would blend in better...