You'll have to stop by your local specialty shop and get the proper adapter. The XM will use what is known as a Motorola adapter (pretty standard for many years) and source the male/female adapter for the Subaru. Metra sells one that is part number 40-SB30. This should be both male/female for both the Subaru and the Motorola connections. The antenna connection is down in the console on the drivers side. Check out Taiguy's install log to see where it's at.