subs and box

I just purchased a       Infinity Kappa Perfect 10 DVQ 10" Die-cast Subwoofer and a JBL GT5 A3001 300W Mobile Subwoofer Amplifier and i also have a pioneer gm5300t amp. This is going in a 2001 silverado extra cab i have infinity reference 6.5 for the front doors but dont have any for the rear yet i have done a few systems before but i want to make this one right. How would the best way be to build a box be without losing my back seat? Is this equipment good? Im not entering any competitions just want a good clean sounding system. is there anything else i need besides rear door speakers? Thank you for your help in advance.

Building a box to fit under the back seat is obviously an option. Also somethin you might wanna look into is building a center console enclosure.UNLABELED Custom Car Club President

I have bench seat so no console box. would my sub fit under seat with a correct size box.

Your subs have a mounting depth of 6.5" Using 3/4" mdf the total depth is gonna be 8" at the VERY minimum. Just measure the space you have under the seats. As long as it More than 8" you should be ok.UNLABELED Custom Car Club President

Its 10 at the front and 7 at the back and from front to back its 15.

Sounds like a pretty tight fit. But if build the box where its a lil less than 7" at the back, and 8.5 to 9" at the front you should be ok. Then of course place the sub as close to the front of the box as you can. Your box is really gonna need a lot of measuring and planning. But if you take your time with it, it should work out.UNLABELED Custom Car Club President

Would that speaker be ok building an open air box?

Also my amp is rated 175w rms x 1 @ 4 ohms 225w rms x 1 @ 2 ohms 300w rms x 1 @ 1 ohm My ? is there are 2 speaker outputs and i dont believe its bridgeable so if i run 2 subs what will my output be with 2 Infinity Kappa Perfect 10 DVQ 10"

Connect one voice coil to one set of terminals on the amp.  Connect the other voice coil to the other set of terminals of the amp.   Your amp will put out 225 watts in this configuration.