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That display is probably a screen technology called STN, which is pretty crappy. Also it only has composite input, and the resolution is only low (320x234) which is too low to display much clearly.
It would be MUCH better if you save up for a few weeks more, and get yourself a VGA TFT, you will be shocked at the difference. You ever seen a computer try to display text on TV-Out? You seen how blurry it is compared to the monitor?
If you don't believe me, or want to see for yourself, check out this post in the FAQ in the "Newbie" section, it should explain it all much better than I can
The display is one of the most important parts in a good carputer setup, so don't scrimp and save on it The same applies to the power supply. Without good quality power or display, you can't see anything, because it's too blurry, or it won't even have power