How bout installing right and not blowing the sub? If your trying to get every last inch of space, seperate enclosures will not work, and they are more expensive to build, more chance of messing up the enclosure. And if you can't tell a sub is blown, something is wrong with you, a 3dB decrease in sound should be more than noticable, plus it isn't hard to unplug the speaker wires and put a 9v to it and see if they are blown.