I replaced the HU-611 with the HU-801. No more tape deck but I have now a 3-channel system. Works great. I added the center speaker (wired) and a PA-300 amp beneath the passenger seat. There was power wired for the amp but I had to add a harness from the head to the amp. $50. The rear speakers now bottom out. Too much power. I need stronger rear speakers. Any recommendation?

 

What year is the S80? I have a 2009 with the Dynaudio system and think its pretty good...