The equipment is over thirty years old and the manufacturer spec is hard to find. The management in my building has allowed too many people to touch the equipment and now I have identical pumps with differantntypes of filters, bearingrgns etc...
I do whenever I can. Especially when the equipment is 30 years old. A 300 hp motor and a large pump like you describe isn't something I would take chances with, especially if replacement was not in the forseeable future.
There are times when there are acceptable alternatives or availability is an issue. Cost is not usually a deciding factor.
I could really launch into a rant right now, but I will spare you.