Rok

I am the new owner of a 2012 Fusion SEL AWD. Optioned as it is, it came with a SYNC system in it, which so far has been fairly straight-forward to programs and pair my phone with. I totally love the 6-speaker stereo in this car and a pretty vast Blues collection on my phone makes the stereo worthwhile. I do have a question someone here may be able to answer; I'm not an electronics person but I'm interested in buying some kind of device which I can leave in the car that is dedicated to nothing but music library interface to car radio. I have (currently) like 9 GB of music on my phone and a recent "Spotify" online music service pretty well guarantees that this will only be the beginning. Can anyone recommend a Spotify-compatible music player with gobs of storage that I could use for this? After getting my (Motorola Atrix II) Droid phone a couple years ago, I immediately upgraded the SIM card to 16GB, 14.3 of which is now used. I might be trading (up?) to a Moto X soon but whether I do or not, it's clear to me that a phone or personal computing device does not maked the best platform for mass music storage. I really WISH Spotify would allow downloads onto a flash drive but due to the nature of their service, it's a device or nothing. Hope some of you have some suggestions. Thanks for your consideration and I'm glad to be here! Rok