It's a bit grainy, and that will only be magnified when printed. It's also not really formatted for the size of a typical marquee(unless your cab is extremely narrow). It'll either be stretched out to fit the width of your cab, or it'll have to be cropped to a wider angle, which will cut off the top and bottom characters, and magnify any image artifacts.
Maybe reduce the number of portraits down to two rows only(no one will miss the other characters not shown), enlarge the text and align it to the left side of the marquee, and let it take up 3/4's the length of the marquee. Then on the far right of the marquee in the unused space, pick to of your favourite characters and enlarge them way up and have them in a close action shot.
Here's a quick mockup of what I mean:
