I have a 2013 Legacy Limited. I have noticed with my iPhone 4 that Pandora and music on the phone will work fine with bluetooth and USB. However I cannot play youtube videos. It plays for 2 seconds and stops every time. I have tried it through the USB and the bluetooth. Same thing happens. If I keep hitting the play button on my phone, after several times, the phone will have the connected symbol lit up in the youtube app and the song will play however I cannot find where it is playing to. I played with all the modes, still can't find it. I got youtube songs to play once though the car speakers on bluetooth. I haven't been able to figure it out since.
I currently have iOS 6.1 installed on my iPhone. There is an update available for my iPhone. I just haven't done it yet.