I'm making a new sub box for my wagon (fits behind the back seat) current one does the job fine, no dramas there, it's just a bit tacky as was knocked up pretty quick.
But I'm wanting to extend it further and box in the left/passenger side aswell, mount the amp and capacitator there indented.
I was just wondering if maybe I should fit another sub on the left for s**t and giggles aswell.
I've already got a 15" in the big box and an 8" in the front passenger door (or will be when my door trims come back from old mate whose doing the fibreglass for me - he's making 4"s in the front trims for the 3 way splits, and an 8" pod on the passenger side for a front sub - as I don't like loud bass, and was finding either the 15" in the rear was too quiet or too loud).
Any thoughts/ideas?

do you need another sub? is there anything to be gained from getting another (ie wiring in parallel to run amp at lower impedance)? if so get it