Is anyone using an aftermarket head unit with the Harman/Kardon amp and speakers? Crutchfield says they have a harness that will allow you to retain the Harman/Kardon setup and just replace the head unit. I'm thinking of doing this because I don't want to spend the $$$ for the factory CD changer and this way I will have a CD/MP3/WMA player and also an aux input for sat radio for later down the road. If I wanted then I could even use a CD changer later too, plus I don't have to figure how to make the factory sub work with an aftermarket unit.