2006 S40... I want to make minimal modifications to the car, but want to maximize sound quality and use my iPhone. I want to keep the waterfall stereo as it is. What are my integration options? I don’t want some kind of cheap kit because they all end up with SQ issues. Can I tap into the wiring harness somehow and somehow connect to a line-in? Seems like there are few options. Has anyone made a change like this, and if so, how did it work?