I would replace it with a 16ohm speaker. That way if ever you want to use another extension cab, but one that is also 16ohms (doesn't matter if it's a 1 x 12, 2 x 12 or 4 x 12 as long as it's also 16ohms) you just set the amp to 8ohms ASSUMING YOU WILL BE USING THE INTERNAL SPEAKER AT THE SAME TIME. Hope this helps? :)