BOSE Equipped Vehicles:
2005 - 2008 vehicles with BOSE use CT51-PO04.
2009 - 2011 vehicles with BOSE use CTSPO007.2 ( retains SWC as well)

BOSE Equipped Vehicles:
You may also consider replacing the BOSE amplifier completely (if equipped). You can view amplifier replacement options below:
Amplifiers - CLICK HERE

The Porsche subwoofer in this vehicle has a BUILT-IN amplifier, driven by a low level signal from the OEM amplifier. When replacing the main Porsche amplifier, using a 4 channel is suggested as the subwoofer in the vehicle has it's own amplifier, you can connect the subwoofer pre-out of the aftermarket radio to the low level input of the subwoofer amp (from Porsche). OR, you can use a 5 channel aftermarket amp in the vehicle and replace the OEM subwoofer with an aftermarket subwoofer.

In these cases, use 70-1784 or 70-9003 as simple wire harnesses to preserve OEM wiring behind radio.