I've got a 2006 GMC Sierra that I'm building a system for. I'm going with a 5 channel amp, 4 of them for the fronts and rears, and one for the sub out. The sub channel puts out 600 watts rms @ 2ohms. I'm going to get a under the seat box for it using dual 10's. Now the possible crazy part I was thinking about was this. I'm thinking about adding a third subwoofer utilizing the OEM location, it'll be a small 6.5". I was thinking if I were to use a distribution block and get all three subs rated at 200 watts rms @ 2ohms I could do that. Would it sound like crap though? Not sure if anyone has done this or utilized the OEM location with an aftermarket sub. This is the seven speaker BOSE system and while I was driving home, I was feeling what little bass it puts out and came up with this thought. My other thought was that having a sub between the seats I would be able to increase my xover point on the front 6.5" components since the bass is right there, maybe cross them at 85 or 90 and keep the sub channel up that high? Your thoughts please.