what if he's happy w/what he's got and is just looking for a boost on the high end? He also may not have the $$$ for some components.

Installing just tweeters is neither ghetto nor ricey. Sometimes, you just need a boost on the highs, in which case, get some tweets, flush mount em, run em off an amp that is capable of putting out the rms needed to run them and go on about your business.