I recently found a great deal on 5" Sony lcds made for their playstation video game system. They have A/V inputs, with vga, component, and s video mods very easy to do... so i bought all of the units the store had left @ $40 (6)

Well, among other uses i've found for them, I've decided to try to pop a couple in my 92 240. The best places for the front passengers seem to be in the sun visors... the lcds fit within the visors and the visors dont fold down even when i put the entire lcd (prior to any dissassembly) up inside them, trucker-style. But I dont know about the foam material the visors are made out of, it may prove too weak for mounting purposes. On top of that, I'll need to power the lcds (only 5v, approx 1 amp each), the xbox-based computer they will be displaying, and the amp I already have in the trunk. I've never done something with this degree of specificity, particularily on a dc system, so i dont really know what to be watching out for. Any help woul dbe appreciated, and any feedback to my thoughts is as well.

(1) Is a single battery w/ the stock 92 240 alternator (recently replaced) enough to adequately power this system, through a power inverter obviously?

(2) What is the name of the component that is used to maintain auxillury power when starting a car?

(3) Is there a place where aftermarket visors can be purchased, ones intended for modification like this?

(4) What am i overlooking?