Wanting to Upgrade your Steering wheel to Multifunction but have a Aftermarket stereo like? :
• Kenwood
• Alpine
• Pioneer
• Sony
• Clarion
• JVC
Then you will most likely need one of these.
Otherwise the steering controls may not work. You need this in addition to the STMV1.
Works with most Porsches PCM of 4 or below:
• 911's 997/991,
• Cayman/Boxster 986/981
• Cayennes both gens
• Panameras
Bonus: It will also enable other features to work:
Ignition, parking light, vehicle speed sense, hand brake, and reverse analog signals in some vehicles.