If you're talking about the speakers in the console, they're not really tweeters they are presence speakers. Not necessary at all, the THX systems don't even have them.
For the best imaging, you want the distance between the left tweeter and your left ear to be as close as possible to the distance between the right tweeter and your right ear. You also want the tweeter located as close as possible to the midbass. The factory location is actually a very good choice, down in the kick panel is even better.