I've got a huge upgrade coming up within a week.

Delivery is due Thursday (6/11/2009) on a
JL Audio HD 600/4 amp and
JBL 660 GTi component speakers. This may increase my gasoline consumption.
My question for those in the know, regards installation of the tweeters. With the
highly recommended (but optional) 'waveguides' each require as much space as a 4x6 inch speaker. Without installing the waveguides, it
might be possible to mount them in the plastic triangle pods ... as done by
4smartcar with their Focal offering. But, with the waveguide I see two possibilities: in the door (near the top below the window, rearward of the woofers?) or in the top of the dashboard. In the photo above, you can see the tweeters both with and without the waveguide, at the center of the photo.
So, are there technical reasons to rule either of these locations out? If not, would one give more satisfactory performance over the other? Is there another, maybe better, location I haven't considered? These are high end components and installation will require modification to the car ... I wanna get it right.
Oh, and the crossover is about 8x12 ... where might I have that big thing placed?

I'm planning to have the amp installed under the passenger seat.
The woofers come with two trim rings, carbon fiber and leather. The leather is brown, so doesn't match my interior. Not a huge fan of carbon fiber and that won't match anything in the car either. Maybe the install the speakers without the trim rings. It may even be possible to mount them behind the stock grill, as I did my Polks. Stealthy upgrade, haha. But, I don't know if that is possible til I set eyes on them.
I will be having this installation done by a pro who has previously worked on my car. Your thoughts are appreciated.