Help adding amp & sub to JBL system in a DC

Hi all, I'm thinking about building a dbl 8" or 10" box for my 2008 DC. I have a vr3 400w amp but haven't chosen the subs yet. I like the JBL system but would like a little, or a lot more thump. My concern is how to tap into the existing wiring to feed the amp. I've searched for a wiring diagram and not found what I'm looking for. My initial box design (working left to right) mount the existing JBL amp, 10" sub, vr3 amp, 10" sub. Or possiblly just a single 12" (shallow mount) in the center. Perhaps there is a T-harness designed for this? The vr3 only has rca inputs. I doubt the JBL HU has rca outs not in use. Any thoughts out there? Thanks.

 

Have you read through this yet? http://www.tacomaworld.com/forum/au...uble-cab-complete-audio-install-tutorial.html

Good information packed into there

 

I was just at best buy and seen this and it looks like it would easily fit in the double cab and for the price of sub and enclosure it seems fair! Just not as good looking as one thats meant just for the double cab. Its the fosgate p3 shallow sub P3L-S12.

http://www.bestbuy.com/site/olspage...allow&lp=9&type=product&cp=1&id=1202650467630

 

Thanks dgerm, I scanned thru that post but didn't see anything about tapping into the existing JBL system, removing the factory sub and adding an amp & sub.