there is a minimal improvement but it is not ties to any performance increase. just a better overall operation. think of it as increasing your arteries by a small %. it wont do anything to help you run faster or longer, but will be more likely to keep you from having a hart attack or stroke.
Its a $20-$30 change and if your replacing wiring, why not go with a larger gauge. some people go crazy, the guy I got my car from went what I think was a little over kill and had 6 AWG all over the engine bay tying grounds all in 1 large daisy chain.
The typical changes are in the Ground wires from the battery to the chassis and Motor to battery. Positive cable from Alternator to battery, and from battery to starter.
2001 ZX3 2.0L Zetec-
Hatch Nation #42
Going through Rebuild See "The TICK Build Thread" for details (http://www.focusfanatics.com/forum/showthread.php?t=289168&referrerid=62897)