The new Android head units available for cars are pretty much just a tablet fixed in your dash. You can use regular apps like Spotify or Tunein which is great. On an iPhone you can go into settings and enable hotspot which shares your internet connection, this will turn off wifi on your iPhone until you disable hotspot. On my Mac I can see the hotspot without it needing to be enabled, Ive read that any device signed into your iCloud account can request the hotspot without it needing to be turned on first, if that makes sense. Is there an iCloud app for android? (not just an email app)