Ive have used a PC PSU to power a 12" pioneer TS-W305C sub and amp at home. Its a 250 watt RMS amp powered by a Silent 700W 40A @ 12V power supply. It sounds amazing is extremely powerful and can handle high volume with ease. The power supply doesn't even get warm but the amp does when driven very hard, but it is designed like a large heat sink so its fine. Its a sealed box and the only other thing ive done to it is put some Dacron fleecy lining inside to dampen it. The wires were cut down and soldered to larger wires for the power and ground so it looks a lot neater. I am going to add some good spikes to the bottom now which may improve the sound further and to finish it. I know it doesn't have the same finish and build but I would love to put it against a home AV bk electronics xls200 or even a xxls400 sub woofer to see how it compares. They cant be that much if any better and this was a fraction of the cost.
I have owned a Rel Quake and a Paradigm PDR10 and this is more powerful and better in my opinion. Being the way I am I also took both these subwoofers apart to look at there construction and this car sub woofer looks far superior in its construction.
Having a bit of fun with it at the moment but I would really love to try it next to a xls200 and a xxls400.