For removal, I’ve always used an air impact, and a pair of vise grips. The condition of the one you’re taking out doesn’t matter.
Installation is the hard part. I normally put it all together, then torque it after I install it back in the car, with the weight of the car helping to hold everything still.
I can’t find a special tool listed anywhere…however, I also don’t have access to a proper maintenance manual for either of those cars. My guess it that it’s simply a fitting used during the manufacturing process for the central rod in the strut, and not a slot for a special tool.
Chase