Just curious why some installers do not remove factor wire from alternator to starter (and eventually battery) and some do. I am preparing to do a full install on my 2013 GMC Terrain and the factory wire (fusible link) is very small. It feeds nothing other than the starter on its path to the battery. I am planning on upgrading the alternator to a higher output and am pretty sure it will exceed the limits of the link. But if I wasn't upgrading the alternator, what are the benefits to wiring over existing harnesses? Seems logical to upgrade and discard old harness.