wiring aftermarket hu

I will be installing a Kenwood KDC-X889 in a 2001 Mazda B3000, my question is whether use all factory wiring. Will running +12v and Ground straight to the Battery improve the sound much or necessary since the unit is rated at 22watts RMS x 4? Will running aftermarket speaker wires improve sound quality greatly? I did replace the factory speaker with Kenwood KFC-C6879ie about 2 years ago [vast improvement over factory speakers] Chaos

Dont run the wires to the battery. Check the information that came with the new head unit. Some head units specifically tell you not to use the constant wire in the factory harness. I had a high powered Alpine that pulled alot of current. For what you have, it sounds like the factory wiring will be sufficient. It just depends on how much free time you have and if you feel like running new wires. I dont think you need to, especially if you are just running the headunit directly to the speakers without an external amp.