Voltage Stabilizer

Are voltage stabilizers any good? They all say they do:

*** Increase Torque
*** Increase Fuel Economy
*** Increase Engine Response
*** More Smooth Acceleration
*** More Stable Idling
*** Quick Engine Start
*** Less Engine Noise
*** Increase Headlight Brightness
*** Optimize Battery Life & Audio Sound Quality

But is this true? I've got a couple voltage stablizers for my guitar and recording gear, and there was a difference. I was wondering for a car if it was worth it. They're not too much money, so I'll probably pick one up anyways. Here's a link to one.

http://cgi.ebay.com/ebaymotors/Nissan-Primera-Cefiro-Cedric-Voltage-Stabilizer-NISMO_W0QQcmdZViewItemQQcategoryZ33577QQitemZ80723 39580QQrdZ1

Thanks

I'm sure it does something, and it probably wont hurt. Although you'll have a "nismo" part or your dsm...

Junk.