Yeah, it is all preference. Kick panels sound very good, but can be impracticle(sp?) in some daily drivers, i don't want them because i would have to lose my dead pedal, and my foot would be sitting on my speakers when im not shifting. I personally have mine mounted in my door above the handle in my civic. It sounds fine, not a big fan of my tweeters but money doesn't grow on trees. So my advice would be get a few feet of speaker wire, mount your midranges wherever you want, then get some doublesided tape and tape the tweeters in all kinds of rediculous places in your car and figure out which sounds the best. If you feel your tweeters sound bad, like kinda harsh and waht not, try reversing the + and - wires on ONE of the tweeters, it was like night and day in my case. But like Redford said, you could put them in the sail panel, higher up in the a-pillar, stick them in the door very close to the midrange firing up at you, where i have it, hell on the dash facing you, it is 100% preference, so do whatever you want and what sounds the best to you. I apologize for the length, college essays are getting to me.
-Jason