A little misguided......here's come clarification:
Composite refers only to the type of CONNECTION (think about the white, red, and yellow cables we used to connect our 8-bit Nintendos to TV). Connecting your CarPC to your screen via composite input will make small text hard to read. A better (and more expensive) choice is to find a screen with a VGA input and resolution, allowing you to transfer a much sharper image to your screen without sacrificing quality. VGA screens (such as the Xenarc 700TSV you mentioned) allows for easy viewing of text in navigation programs, among others with small fonts.