Also bought the W103 Pro for my Audi as the Bluetooth appears to be faulty, constantly drops and is too old for carplay.
Very pleased with it, only problem is it needs to sit where the Audi's MMI screen would pop up out of the dash. I've removed the fuse so this cannot happen, however.........Unless the MMI is raised it is not powered on, meaning I cannot connect the W103 Pro to the cars speakers.
(I test fitted and connected it using the FM as the bluetooth is faulty and it worked flawlessly)
So I can only use it with the built in speaker which isn't great.