Subaru Subwoofer Reverse Wiring Harness
This harness has the connector that plugs into a Subaru factory subwoofer. Wires are approximately 5.75" long. Not available anywhere else (other than as part of the factory T-harness for the subwoofer -- price more than $80 from dealers).
The wires have the same EIA-standard color-coding as other after-market harnesses, with text labels (for example, "Left Rear Speaker +") and pre-stripped ends ready for you to crimp or solder. There are 6 wires:
Price $12 each plus shipping.
For more information and testimonials from satisfied customers, see this post on the Subaru-SVX.net forums.