sent a long reply to your email last night, forgot to include that the factory amp divides the signal between the front door woofers and small dash speaker; most likely you'll combine them on your front channels and you will need to use a passive crossover to keep low frequency out of the dash speakers, or they will blow. it can be as simple as a 100-400Hz non-polar capacitor inline on the positive lead, couple bucks from radio shack.