[JFreak]

As said, on Mac the PT app is self-contained, has everything in the app package -- except support files, such as preferences and such and even then the only problem is if newer version stops using a file that was needed for older version in which case that file is left there doing nothing.. not much of a problem with the storage capacity today. Every time you launch PT the app copies over all included plugins so you don't even need to worry about plugin versions.