Another solution is you can make your own harness with these two items:
https://www.sonicelectronix.com/item...a-71-1761.html
https://www.sonicelectronix.com/item...che-TA02B.html
you would need to find out which speaker is which on the OEM audio AMP and solder the connectors with the new custom harness. then un plug the factory subaru amp and plug in your custom new harness.