I bought all of the parts on Ebay for A$10 or around US$7. very easy to install and it works well. This was done on an Australian spec. RHD 996 Carrera 2, I"m assuming the US and Euro models have the same amplifier with the stock radio/CD.
Parts were bought on Ebay.
1] A small Bluetooth receiver.
2] A 3 metre 3.5mm Audio cable.
3] A splitter to convert the two outlets on the side of the amp. to a single stereo audio cable.
Connect the splitter to the amp. which is located in the front luggage compartment, run the cable into the cabin, I drilled a small hole to the left of the battery compartment and ran the cable through a rubber grommet sealed with silicone.
Positioned the Bluetooth receiver beside the steering column under the dash but where it can be reached for recharging.