The woofer replacement is simple.
Joe can tell you about it but no, soldering is not requied. It will be a simple wire clipped into the back.
Just don't use anything that could damage the finish when popping out the woofer. One of mine was a little sticky in the hole but i just kept teasing it with my fingernails until i could get a good grip.
You can always pop out your woofers now before joe sends a new one, swap their locations and see if the buzz noise moves in relation to your woofer swapping. Might help you to figure out which one(s) is buzzing.
