Last I poked around with this I came away with the impression that the app files need to be "signed" with a trusted certificate. To get your own app files to be accepted, you'd need to get your public key added to the trusted key store. Being that I'm leasing, I'm a bit hesitant to pursuit rooting the system.
I've given up and grudgingly accepted that I have to BT stream Pandora and deal with the inherent limitations of waiting for a stop light, or parking to update what's playing. This is my second Infiniti, and is increasingly looking like my last. My G25's power steering growled and vibrated on low speed left hand "parking lot" turns. Twice to the dealer, and twice refused to acknowledge/correct the problem. Last go around didn't bother to even drive it a single ******* mile (checked OD). Fortunately my Q50's mechanicals are in order, but the electronics lack any semblance of polish, or even completion. Back up camera has stayed on twice now; most recently I touched the handled to unlock only to have the alarm go off; Bluetooth for the longest time kept locking up, though has recently stabilized; phone dialer loves to initiate calls then drop; address book has hard time figuring out if it should merge entries from different accounts on my phone. Drive the car one day, ask to call my wife and it will select the number and dial. The next day it will present me with two entries for the same number, and ask me to choose, one from the phone's memory, the other from Google.
The IS350 and the Model 3 are looking more and more interesting the longer they leave this BS unfixed, and refuse to communicate with their customers about any of it.