Oh yes sorry, I read your reply wrong. I am replacing all of them. But the big question is: what do I replace them with?
Here is how I would approach the "problem".
Now that you have a budget number-subtract the "KNOWNS"-wire-labor-hopefully a new amp etc.
So now you have what is "left over" for the speakers alone.
You divide that by the number of speakers.
NOW you have a number that you can ask "What speaker would you recommend for my application that costs "X" (the number you came up with)"
Until people have some sort of an idea of budget-it is hard to recommend anything USEFUL TO YOU.
Remember that anything that is recommended needs to include a 70V transformer cost.