I had this unit professionally installed with the standard $50 wiring harness made for Honda vehicles. My car is a 2004 Honda Element with OEM stereo. The first notable thing was my radio no longer had close to the volume it had before the install. Second, when receiving an incoming call, the radio would not mute completely, resulting in me having to turn down the radio. Third, my music would be incredibly bassy, and no amount of adjustment could compensate. The installer tried to trouble-shoot the problem, install a relay to shut down the radio when calls come in, and made calls to Parrot tech support, which gave them no solution to the problem. I had it removed from my car and ended up eating the install fee. I really liked the convenience of the parrot, but for my car, it was not going to work.