Same as aviator, I've done the negative side, and it made a big difference for me in headlights dimming at high power draw. In the interim, I've also gotten an Optima Yellow-Top, which I'm sure doesn't hurt either. Anyway, I think it's a worthwhile upgrade, especially when you see how small the ground wire is on the back of the engine.

 

might you happen to have a photo to help me locate exactly where that small ground wire is on the back of the enginer?