Um , why do you need a WiFi connection for download compiled playlists?
streaming is a lot simpler than ripping or the absurdity of leaving physical copies in the attic and then buying a storage solution when none is needed. Given the fact you are in a car you are not going to be using speakers that will give you fantastic sound quality are you.
It's happening chaps the unavoidable fact that soon everything will be available to stream in cd quality or higher and it will be available from one hand held pocket sized device that pairs with your car stereo, active speaker or old style hifi , actually it's already available
unlimited data , WiFi etc bye bye cables ,collections , Nas etc. Just the ability to type or ask your app and bingo!
I will stick with my records because I am old and I will play c.d because I have so many.