Like most of you, we found the 2012 OEM (Non Nav) head unit alittle to be desired.
Some of you spent lots of $$$ to upgrade to aftermarket units, amps, and speakers.
But on a limited budget and use of the same head unit, and factory speakers I found a quick upgrade to the sound.
I recently purchased 2 items which made this upgrade easy and fast with a minimal effort and skill level.
1) Purchased a Alpine KTP-445U 4-Channel Amplifier.
2) Wire harness with forward and reverse plugs. (Made by Mr. David Carter)
The web site to order one from is: ae64.com - Subaru Radio Wiring Harness - Order Form
I purchased the 20 pin combined "breakout" wire harness.
Simply cut the longer speaker wires in the middle somewhere and connect the amp in between, then plug into the head unit and factory 20 pin plug and your done.
Wire colors are exactly the same and made it super easy to wire together.
Now turn on your head unit and set the out put gain on the front and rear on the amp following the instructions but mostly to your listening ear.
Replace the head unit and AC vent then the front grill and your done.
I must say the volume level before the install was at 9-15 when driving, sometimes louder just to hear the radio or CD playing. NOW its at 5-9 and its very loud to me.
So if your looking for a easy, cheaper upgrade you can try this out!