It's DEFINITELY worth the upgrade from cs5. After Effects cs6 is much better, Premiere has a much cleaner layout and is a bit faster, and Photoshop added a ton of new features like the content aware move and more tilt shift blur effects.
After effects has a free 3d tracker and ray tracer which is just amazing.
I wouldn't torrent it, just download the trial, and then paste in the crack files into each programs folder in the program files.
Should be something like C:\Program Files (x86)\Adobe\Adobe After Effects CS6\