I love my FI system, these 2 tens are just stupid loud....(for me anyways!!) my dash flexes my steering wheel moves around the outside body panels flex. And they play VERY LOW as well, i cant describe how good they sound but maybe this will help, my wife has a 12" MTX 5500 in her car and dont even want to listen to it because the bass sounds funny/strange after hearing music with FI, the MTX wont play nearly as low, i never knew what i was missing! as far as the cost the Q's were standard price no upgrades on mine (and they are taking 1500 watts each all day long!) a good amp will run around $500-600 i got mine from ebay, the seat lift kit was $150 google LMI high rider kit, and the box - install i did myself, i just fabed it up in the truck while i was making it, i kept each sub in a .5 cf chamber after displacements (as per Nick!!) i also kept 2" from seat bottom to top of box so i can play it full tilt with the seat down, also you need to leave around an inch on the bottom of the speaker for the cooling hole (if you look at the bottom of my box you will see the square cap i used to get more room) I have recently upgraded my stock 5x7's as well you will not be able to hear them when the subs are broke in and the bass is up! If you check out F150online.com look into the speakers and subwoofers section of the forum a lot of people have been squeezing 12's into our truck, but you loose the room for PS2, and your seat wont fold up and down. ya i love ur set up i wanna do the same thing. the 04 and 06 are the same dimensions in relation to the back seat room correct? could you make another box like yours and id pay you for it. cuz from what people have told me it is expensive to have one made at a car audio store
