Well you got two paths now to the fuse block from the alternator. True, it will for the most part, take the path of least resistance, so the vast majority will be carried by the alt. re-wire run, but you still have some going across that original wire thats considerably smaller and pushing about 8' in length.
From just purely an electrical standpoint, Id want all the power going across the one wire. Unless you're keeping the stock wire in there for back up, and at that point if that is the case, why not install two alt. rewires?
