i have just got a 98 silverado ext. cab, and i am looking for a system. I am definitly using an Eclipse deck, an Eclipse 6 3/4 component system, a pair of Eclpise 4x6 coaxials, and a PPI 400 watt 4 channel amp, but i am not sure on what to use to take care of the low end. I thought about 2 JL W7 18"s, but i want the back seat to stay in. Do you have any suggestions?