wired remote or head unit that display/controls pandora or spotify
 

I have been looking to upgrade the head unit in my boat as the current one does not have a auxilary input.

Does a wired remote or head unit exist that you can control an app from like spotify or pandora?
Basically hooking up the USB cable and using pandora/spotify from the deck or wired remote the same way you would control it on your mobile device?

Also, is there a difference in any of the auxilary inputs on decks, as far as sound quality goes??

Thanks!

A Kenwood KMR-440U and iPhone 4 with Pandora and the headunit controls the tracks in pandora. I have not tried to change stations, truth be told I just realized "next" worked in Pandora tonight.