I’m trying to figure out which blitzsafe (or other brand) connector/switch to buy. Here is what I own.

2004 Audi S4

Audi Bose premium stereo

-XM Radio = yes
-In Dash CD = yes
-Trunk music CD changer = no
-Audi GPS NAV, Data CD player in trunk = yes

What are my options to get a nice line in so I can play my iphone through my stereo? A tape adapter is not a good solution as its too noisy and messy.

Also, do they have any retrofit systems to use my phone with the OnStar phone system? The onstar system is useless since the service is no longer available even.

Thanks!