In a car, most times things will sound best when the source is as far away from your ears as possible. Just seems to help with imaging and soundstage. Also, those quarts tweeters tend to be on the bright side to begin with, so the closer you put them to your ears, the brighter they'll sound.
I've seen some competition cars where the owner has actually taken out the front seats of a car and moved the steering column, gas and brake pedals to the back seat, just for sound quality competitions. Obviously that's taking it to the extreme, but it was still cool to see... and sounded great
Scott, those speaker pods look like they may be ok too, you'd have to do some trial and error between those and the stock locations.