Just fininshed installing my box under my tonneau - single 20" ported in between the seats, totally lined the bed and box with MEL ROLL - a heavy, sticky backing that's applied to cement wall where they're going to have dirt back filled against it - it's heavy as hell and about ten layers stops all vibration (but it weighs man so be carful) This is the power tonneau I used, probably the easiest and most satisfying installation I've ever done on anything:
http://www.thehoffmangroup.com/autoloc/product.lasso?prodinc=tonneau