No, the CoolStream Duo does NOT work in the 2008 Infiniti FX.
The CoolStream Duo will not work with the iPod cable in any Infiniti model built-in or after 2008. For more information about car compatibility, please check out Car Compatibility – Testing Results
For Infiniti models built in 2008 and later, the CoolStream CarPro is compatible with some models. Please check compatibility before purchase.
Please note that the Duo will work with all car stereos with a 3.5mm auxiliary jack.