I would put the component crossfires in the front doors. Buddy of mine used to have a full crossfire system in his scion and it sounded amazing. Even with the subs rattling off interior panels in the hatch you could still hear the highs. Beside that why buy something when you already have something good to put in there.

 

The Pioneers in the doors are staying if I can help it. I'd use the Crossfires either in the rear or dash.

 

Not worth the hassle, Also you want the speakers to handle more wattage that way you wont blow em out