I'd like to wire an aux input to my factory headunit and connect a Sirius radio to that. Do I need to purchase one of those $60-$100 aux/ipod adapters from ebay or can I do it a less expensive way? I have an '08 Mazda CX-7 I wired with a custom harness for $15 so I'm wondering if there are instructions or others on here who have done it?

What are my options?

 

There is a Sirius recvr for the head unit, so I bet there is a connector in the parts catalog