yep, you should be able to use both.

it sounds like you are missing the passthrough cable, see the description here from BSW:

The BSW Sirius Direct system connects to your existing CD Changer connections in your trunk. If you already have a CD changer or other device that uses the CD changer connections, or you intend to add one, you'll need to add this passthrough cable which creates another set of connectors after the Sirius unit.


http://bavariansoundwerks.com/produc...ite-Radio-E53/

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