Our SAP system doesn't support Polish so we use GlobalTextReplace and TextReplace to provide Polish translations for the required fields (and remove the unnecessary fields with DEL function).
Are there performance differences between using GlobalTextReplace and TextReplace commands?

Even a relatively large number of GlobalTextReplace (several hundred) will not create a performance problem. But if you expect certain screen elements to be displayed on one particular screen only, I suggest you use TextReplace instead.