D Celt, it sounds like you're all fixed up. At two watts, your CB is producing less than the legal max of four watts, but the practical difference between two and four watts is practically zero. Those two extra allowed watts are not likely to make any difference regarding distance or quality to the receiving stations you might talk with on the highway. I will note that all of my CBs are less than four watts, and one is right at two watts like yours is. It works as well as any of the others I use.
About the question of removing the mag mount to get into low-ceiling parking spots, no problems at all. In fact, that's the main benefit of the mag mounts: the flexibility of easy installation and removal. Indeed, I only put my CB antennas on my vehicles when I go on trips. Otherwise, my magnetic antennas are either in the car or in the garage. Same with my radios: I use compact, easily moved CBs, and they are only plugged-up for use in the car when I go on the road.
Oh, and about plugging into the 12 volt port in the car. That's exactly what I do. My CBs draw less than 2 amps, and my vehicles' 12 volt ports are rated at 10 or 15 amps or more. So, there's no problem with using them for the CB. It is often recommended that CB radios be directly connected to the battery. The theory is that doing this could avoid some extraneous electric system "noise" that some cars might suffer from. Fortunately, I've never run into such a problem, and so all three CB radios I have are fixed-up with the 12-volt plugs that go into the cigarette lighter ports.
I use my CBs for getting and receiving traffic and road condition reports on highway trips. It's a great tool for the traveler who is interested in doing that. Even though there usually is not a lot of radio traffic on Channel 19, which is my highway monitoring channel because that's what the truckers use in my area, it's still there for instant use. Channel 19 really comes alive when and where a big wreck occurs and the truckers are looking for and giving information regarding what happened, what alternatives routes they might take to avoid the hold-up, what lane they should be in to best get by the wreck if it's too late for alternative routes, etc.
And about the radio hogs who have nothing better to do than dominate the channels with overbearing equipment, usually I lose them in a few miles of travel. One encouraging though is, if they make a big enough nuisance of themselves, the FCC may get enough complaints to do something about them. There are cases that result in big fines and loss of radio privileges for such inconsiderate behavior,