By my estimation, and based on other similar models it will probably be upwards of $400. Certainly not for the faint of heart. Add that price to a decent amp and you're talking at least $700 for some serious bass.
I was told that the placement of the unit will probably be on the rear drivers side, over the front half of the rear wheel well. It will be in front of the rear 6x9 so as not to block it and will protrude slightly into the storage area from the wheel well.
Hope this answers some questions.
Russ