Um ok these are the claims of ground wires

"HELP PREVENT POWER LOSS AND ENSURE TOP PERFORMANCE OF IGNITION AND OTHER COMPONENTS

LOWER ELECTRIC RESISTANCE AND INCREASE THE EFFECTIVENESS OF THE ENTIRE ELECTRICAL SYSTEM

STABILIZES THE ENGINE AT HIGH RPM'S

GAIN INSTANT HORSEPOWER 5-8HP!!"

Lemme get some feedback guyz. I believe in the fact that they increase the effectiveness of the electrical system...all of it i dont know..but my friend installed some and it got rid of the whole dimming of the clock when u turn the lights on and the rolling multiple windows down was faster as well. I dont know bout the hp gains though

 

I used the HKS Circle Earth on my car. Butt dyno didn't say anything, but my idle is much smoother and my dash lights don't dim when my fan kicks on.

I get multiple mags every month and all have raved about ground wires and that they DO make HP. Not alot, but enought to register on a real dyno.