After doing a bunch of research, I took a chance on the Grom BT3 (SUB08B3) Kit because I wanted to keep the stock McIntosh sound system in my new Legacy, but I wanted to add Bluetooth audio and hands free calling.

My Legacy has the McIntosh PF-40621 (or PF-4062I, not sure what the last character is...). It only takes a few minutes with a screwdriver to pull the stereo out, and plug the Grom unit into the stereo's CD Changer port. Plug in the included microphone for hands-free calling, and you're all set.

Once connected, you can pair your phone to the Grom unit, and press the 'CD' button twice on the Stereo to switch to the Grom's input, and you're good to go! You can also use the stereo's track forward/back knob to skip songs, and answer/hangup calls.

One small thing, I do notice one or two popping noises when the stereo first turns on, but the audio quality is awesome when playing, and it keeps the great look of the factory stereo/interior.

I highly recommend it for anyone wanting to add Bluetooth to their Legacy.