If your going to run the kicker L7 15's (which i say would hit the hardest) look at a powerful amp to power them like the BXI 2010D - Hifonics 2000W 1 Channel Mono-Block Amplifier.
kicker L7, kicker is a name brand compared to sound stream and i have 1 L7 12' and it hits hard, quality and bass wise Kicker, price wise soundstream hope that helps!