I am gonna tell you why. I got a Porsche Taycan last year with Burmester. Its audio quality is excellent, however there are limitations. I can play Spotify from my phone over bluetooth, which means reencoded lossy audio. It sounds awful. I can however play music directly from a usb memory stick, which sounds great, just as it should.
This is more a problem of Porsche, not having Spotify integrated into their PCM. It is coming on future models though. But we with a Taycan 2020-2022 model, will not get this.
So having a pile of ogg files is currently a great option.
I don't know anything about the car's sound system, but aptX is a pretty common Bluetooth audio codec for music and these days it can run up to 420kbit/s with the adaptive codec, or 576kbit/s with HD, 24 bit at 44.1-96kHZ, so it's not unreasonable to think you could hear the difference between high and low quality audio sources with that (since even high quality compressed audio tends to be less than 420kbit/s)
What has been heard cannot be unheard. Back in the day I did some ABX comparisons of various mp3 encoders. I unwillingly trained my hearing to spot encoder artifacts forever. I tested encoders more than 15 years ago. I still hear mp3 compression without trying. Bluetooth SBC codec is even worse. Wish I could turn this off but I can't.
This is more a problem of Porsche, not having Spotify integrated into their PCM. It is coming on future models though. But we with a Taycan 2020-2022 model, will not get this.
So having a pile of ogg files is currently a great option.