A nice, easy way to add bluetooth or aux input to European cars. Replaces the CD changer feature on the stereo, so I'm limited to only one the CD on the head unit. One complaint is that the audio it pumps out is a bit staticy and bass-intense. This may just be a side-effect of poor grounding, so I'll update once I dive in again and check things out.
Need stereo removal keys (you can get away with only using 2, though it looks like 4 is required)