We've done many similar projects before and feel that this project will be easy to complete in a timely manner. To give you a basic idea of how we'll do it: We will iterate through the "Browse All" sections of each category, downloading each file with a simple call along the way. This should be completed by tomorrow, but we set it to three days to guarantee we'll be able to complete on time.
While both are doable, we would just like to confirm you'll be running this on a server (as assumed by the PHP/MySQL tags in the skills).
Thanks for your time!
Haptic Tactics Studios