umm actually i think some of u guys have the wrong impression about sound installs ... tweeters that are placed high up aren't in the best possible spot ... the spot next to the A pillar is easy to do, i used to have mine there, but if u notice, depending on the tweeter, it can sound harsh to very harsh, and the seperation distance from the woofer would not offer you the best sound. however if you place your tweeter there and it sounds ok then i guess you shoudlnt' change it.
The best possible placing is to be as close as you can to the woofer, and also the speakers should be as far as possible to the listener which is why alot of professional installs get done in the kickpanel because thats really as far as u can get the front staging of the install to be. however its a big ask cause its very hard to do. So when i installed my sound system again when i had the skyline, i just cut a hole in the door panel and put the tweeter there, to me it sounded better cause the very high frequencies werent' so dominant anymore.
just my opinion.