2005 4.6L GT
New 160a output alternator - https://www.dbelectrical.com/products/alternator-high-output-160-amp-4-6l-mustang-2005-2006.html
New fused 4 gauge power cable - https://www.americanmuscle.com/premium-power-wire-kit-9414-excluding-gt500.html
Rest is stock
Before everyone says...