I replaced the center channel speaker with a Hertz 100.3. I have an extra one if someone wants to make me an offer. These cost $160 shipped (for the pair from Crutchfield) so no possible fake speakers that are sold on Amazon/Ebay. Thanks!
Do this and be done. Many of us have done it and it sounds fantastic.
https://www.bronco6g.com/forum/threads/b-o-sound-system-complete-upgrade-done-%E2%9C%85.41031/
I called Kicker Tech Support when my 500.1 did not sound correct/not working and he said to check the polarity. Low and behold, I had one of the inputs to the hi-level polarity reversed! Boom. Then it worked!
I was told by The Plug and Play guy, the Kicker Key 200.4 will not do much for the B&O System so don't bother to add it (plus no harness for it). If someone does install it on the B&O, would love to know the results...