Installed in my 2002 S80 T6. No problems (well actually broke a tab on the shift bezel, but it is still functional). Two observations: 1) disconnect the neg battery lead, and 2) Volvo sells a cable that plugs between the radio and the harness giving you a plug with switched power, constant power and a ground. Per USA Spec, I connected to the constant power and ground. No noise, hum etc. Works great and was easy to install.

 

You got a part number for that harness/plug?

 

As you do not need to rejig your playlists to get them to show up properly.
Check it out at http://www.imiv.ca/. They list the power cable part number on the requirements page (can't link you directly to it as I cannot get to the site right now).

I have had one in the car for about 6 months now and I love it.