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If you have the time and knowledge, you can save 20 MB and 14$ by using Quicksilver to set global shortcuts that will trigger applescripts that will resize a window.

This blog post explain who it works (using Apptivate for the shorcuts):
http://mac.appstorm.net/how-to/applescript/build-a-window-management-app-with-apptivate-and-applescript/