Audio Systems: f150 sound system, avic z1, inch subs

Question
QUESTION: i have a 2006 f150 xlt (3doors) and i would like to put in a sound system, i am getting an avic-z1 and two pioneer 10 in shallow subs to put under the front seats i also want to get a 15 inch sub or 1-2 12 inch subs in that back. what suggestions do you have for subs and what amps should i use?
ANSWER: As for the shallow mounts under the seats, subs don't make any sound unless they are in boxes (or more technically have isolation between the front and rear of cone).  so if your plan is to just lay the pioneer shallows under the seats, don't bother, they wont do anything at all.
if you have room in the extended cab the 2 12s would do well.  One thing with subs being in the listening area as opposed to being in the trunk, they will sound very loud but wont have as much thumping feel as systems that have the subs in the trunk.  also you will notice a change in the sound with the windows up or down.
Id be happy to help if you need anything else.
Good luck!

---------- FOLLOW-UP ----------

QUESTION: new plan is to put two 12's in the back and hopfully raised the back seat a bit for more room. i really want loud but good quality sound. im hoing for somthign that would blwo my friedns away. suggestions on subs and amps?

Answer
so you want a box under the seat is that it?  a good way to do this is to build the box with the 2 12s facing down and little feet on the bottom of the box to stand the box up about 2 inches away from the floor.  having a surface close to the subs like that will give them allot of gain and will vibrate and shake the vehicle good.  I did this in a ram 3500 with great success. we did end up raising the seat about 1 inch though.

its not going to be crazy or anything with the restriction of depth and the size of the box but can be pretty nice if you pick the right stuff.  first step to helping you may be if you could measure how big of a box we can put under there.  remember that most of these seats slope back so measure the available height in the back of the seat as well as the front.
Then we'll see what we can get in there.