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Yes, you must remove the water pump (and the balancer pulley) to remove the opti. Due to the labor involved, if your opti is questionable in the least, this would be the time to replace it. At minimum you'd likely want to replace the cap and rotor, but even they're not cheap.
There are probably some good threads with pictures, but meanwhile here's an article:
About the only oddball tool you will need is an inverted Torx E4 bit to remove the opti cap. If you get an MSD opti, it comes with a little makeshift tool for this purpose.