They actually have automotive kits available, they come with a 12v inverter so it's as simple as connecting power and ground. Even have sound controlled options. I'm sure they come with full instructions as well, it usually looks a lot harder than it actually is. They also sell a kit that just uses the cigarette lighter port !
Thats definitely a key thing, from what I've seen, they're typically coloured according to the output they give. Could look very messy very easily if not aligned perfectly straight and in the right areas. Especially if your using high contrasting colours