Sub woofers in the gas tank?!?!?!

I stumbled across this truck on a search for fiberglass interiors. It made me chuckle a little when I say he has an extended cab and it says to save interior space he put the subs in the gas tank. Man the look of custom trucks has come a long way. I wonder what our current feature trucks in magazines will look like to us in 10 years?

http://images.google.com/imgres?imgurl=http://www.sportruck.com/feature/thunder/door.jpg&imgrefurl=http://www.sportruck.com/feature/thunder/1.htm&h=452&w=600&sz=67&hl=en&start=36&um=1&usg=__WgskDXXEUy9VRiR7OH0BrCpWqr8=&tbnid=fMrEzu1du0PvGM:&tbnh=102&tbnw=135&prev=/images%3Fq%3Dfiberglass%2Bdoor%2Binterior%26start%3D20%26ndsp%3D20%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26channel%3Ds%26rls%3Dorg.mozilla:en-US:official%26sa%3DN

he must have another fuel cell or sumthin because there is no way he can do that without ruining his subs

"the last amplifier pushes the two Lanzar Pro 12-inch subwoofers mounted in the stock gas tank. That's right, the gas tank! This is the main reason why the Fuel Safe Cell was installed. We took out the stock gas tank, split it in half, made it into a bandpass enclosure, mounted two 12's in it, sealed it back up with fiberglass, and ported it into the cab. It was something unique that had never been done."