I just finished playing with my new head unit and Sirius.
I am getting sound from the 2 rear speakers, as well as all the others.
The big door speakers are working; but, no longer seem to vibrate my leg.
The High Pass filter does change the sound. The default setting is "off".
Hell, I am kind of deaf. So, I don't know what I'm worried about?
Everything sounds good to me and I love satellite radio, which is why I removed the oem head unit. It doesn't have an input for satellite.