Purchased both the GROM Audio BMWSU3 along with the Bluetooth accessory dongle. Installation in the tight space behind the dash of the BMW 3 series is a bit of a challenge, patience and carefully following along with the many YouTube videos are a must. Once the GROM box and Bluetooth dongle were installed, along with the microphone for the phone, it worked great when I first started the car. However I could not get it to reconnect after restarting, I had to manually delete the Bluetooth entry on the phone and then reconnect to the GROM unit. After contacting GROM about the issue, they quickly determined that the unit needed a firmware update. Kudos to GROM for being so helpful, seeing as how I didn't buy the unit from them. After installing the firmware update through a USB stick, the unit works perfectly, even down to having the phone button on the steering wheel initiating a call. Sound quality on the microphone was excellent - the person I called couldn't tell I was calling handsfree over Bluetooth in the car.