If you use Sub woofers use screws, no nails, re tighten all interior trim screws & loc tight them as the sub will vibrate them loose....neither of my vans have sub woofers....I just blocked the lows to the 6" and blocked the highs to the 6x9 (6 of each)... 12 speaker SONY surround in each...with more than 1 woofer you will need a amp just for the woofers..not just another channel on the amp you now have....
yeah I know , im just waiting till i get better so i can run more speaker wires then hook up the single channel amp.