In regards to the sound level, the kids are usually so engrossed into whatever they are watching that they don't even hear my music or even when I talk to them
I don't listen to the music very loud anyway. The level is usually set so the music is more in the background. I do listen to the music louder when I am alone in the car and occasionally crank it when I'm playing a song I really like
What I've been surprised by is how long the batteries have held up in the wireless headphones. These are still the original batteries and they are going on to 2 years, well more like 1 3/4 years but still...
Especially considering that every time the kids get in the car, by the time I get into the car and start the engine, they already have the headphones on and are ready to start their movie!
I have to say though that the rear entertainment package was worth every penny! The kids are ALWAYS quiet (except for the occasional burst of laughter when something funny happened in the movie they are watching). And if they get bored of watching movies, they usually select the navigation (map) mode and look up interesting places on the iDrive system or they just like to watch the map while I am driving