Thank you, that's fascinating. I might like to do that. I need to get my radio going first and see if it can be heard from the back seat without the rear speaker. I think might be good to have the rear speaker anyway, but first things first. Someone said they had the installation instructions. That would be nice to see how it is done and what hardware might be needed. If I see another Kaiser around, I'll be sure and check out if they have the rear speaker!