It was suggested to me by soundcity, if the tweeters are mounted in the a pillar they should be wired put of phase. I guess if they are far enough from the woofer, the phasing would correct itself. I have not yet installed a system, so I have no idea how this would sound.

 

I've got the Boston Acoustics RC620's and the imaging is great where I placed my tweeters:

 

I was going to do what KaCee did until the stereo shop figured out that the Boston Pro 6.5 would fit in the door with their axis mount option that puts the tweeters over the mids. If you want complete stealth and great sound, this is best thing I have seen. My BA Pro crossovers are in the small space next to the spare tire.