It's pretty much a black box as much as adding things to it. I doubt you're really going to be able to get the caller ID information out of the parrot box to display on your head unit. It is "possible" to get the caller ID information to display on your empeg, but it's only been done once. That being said, I'd gladly give up caller ID display to not have to plug the thing in every time I get in the car. The Parrot already speaks the name when someone calls, so it's not like you'd be missing out on caller id compleetly.

Matthew