The turbocharger is all but a gimmick.

What it does is plug into the ports, then comes back around in a U shape and go on top of the sub.

This increases available port space and lowers tuning frequency without lowering output. They claim a 12 hz bottom limit for their latest VTF-3 HO sub they are working on with the turbocharger.. which is pretty damned impressive. Search around about it on HSU's site.