you're going to have to do a bit of carpentry and drafting. Up to it?
Looks like there are a couple subwoofers made. I found them using Info.com and then went to "Images" and searched using "2004 Chevrolet TrailBlazer sub box" --- http://mediacdn.jlaudio.com/media/mfg/9013/product_image/thm/t670_ 79f34672fa1579874c10ff1f62b238e0.jpg?1322528317 --- http://www.qlogicdirect.com/images/large/C1GTE110_LRG.jpg --
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