do these things actually work, and are they necessary. Thanks.

http://cgi.ebay.com/ebaymotors/ws/eB...category=33574

 

necessary no. whether they work or not is still up for debate. i just upgrade the valve cover and battery grounds. I do it to get the amps a bit more power. I doubt that they will give you more hp.

 

that one looks like some cheap "JDM" copy of the other kits. what the hell is JDM about ground wires. anyway....

these "grounding kits" may be benificial if your current electrical system is crap. in which case itll "increase" the HP, by giving back what was loss due to the bad grounding.

if you have a system in your car and really exceeds the amount of juice that your OEM cables are made for, it may be a good idea to replace the major grounding points.

valve cover to chassis
ground on battery to chassis
alternator cables.

and then make sure that they are secured to the chassis as good as possible. (sanding down the paint so the contacts are BARE metal.)