If you add iPod capability to your 2009-2013 Miata using these two parts:

1. An iPod Integration Module, part number BBM2-79-CFZA, and
2. Harness Kit A4, part number C9FA-V6-029 (without Sirius) or Harness Kit F4, part number C9FB-V6-029 (with Sirius)

You will lose the ability to use the AUX jack.  In that case, you need the item in this listing:

Selector Set/Switching Box part number C9F1 V6 261

This kit restores the ability to use your AUX jack.

Please refer to this Mazda application guide before purchasing to confirm your vehicle is compatible, and which iPod models it is compatible with:

Search for "iPod_Integration_Module_Application_Guide.pdf".  They won't let me directly link to it.

retail $143.95