Probably not enough to hurt anything. Flipside is, you're just paying money for aesthetics.
Circuit boards are ugly, and the whole scene is so '90s-ricer-chic I could vomit. If you want a computer that's more fun to look at than it is to use, ditch the transparent side panel and learn to paint instead.
::adjusts the onion on his belt::
Hell, I've seen so many "pinup" desktop wallpapers, how "aircraft nose art" style airbrushing isn't more popular as a case mod, I'll never understand. (Don't google for either of those at work, btw.)
</rant>