KT. The main reason to put in a voltage stabiliser is to equal out the surges that the battery + alternator release, Raizin voltage stabilisers seem to be the most popular as they are small and compact,, very easy to fit,, the voltage stabiliser is mainly used in cars that are using alot of electrical equipment,, hence if you have a high end audio setup, it is a wise idea to chux one of these little guys in.. plus it will stop your headlights dancing to the subs beats in the boot.. good little invention and in my mind well worth it.. plus if you getter a better ignition spark out of them hey why the hell not.... 10/10 in my mind.. cheers also heres a site that tells you about them.. http://www.the-pivot.co.jp/product/se/raizin-e.html