Playing Audio to Auto Stereo

[Cam62]

My car audio stereo was installed with plug in for Apple device (phone). Stereo is a high end unit. Should I look for an adapter or just stream via Bluetooth? If an adapter would be better for sound quality which one would be recommended and what app should I use to stream? I have my music library downloaded to my phone from my old MP3 player so files are in that format.
Any help would be greatly appreciated as I am new to this.
Thanks

 

[Dannydet]

Bluetooth should work fine, that is what I use, sound quality is very good as long as the mp3s are 192 or above

 

[mikedt]

My car audio stereo was installed with plug in for Apple device (phone). Stereo is a high end unit. Should I look for an adapter or just stream via Bluetooth? If an adapter would be better for sound quality which one would be recommended and what app should I use to stream? I have my music library downloaded to my phone from my old MP3 player so files are in that format.
Any help would be greatly appreciated as I am new to this.
Thanks

What sort of Apple device(iPhone) plug? The old dock connector or the newer Lightning plug?