You can download it and start working with it immediately if you like with no need to wait for shipment.

You can install it right into you existing bb folder and all you stuff will still be there, if you are scared of that you can backup/copy your stuff somewhere else, install it and then check to see if it is all there.

Checking the box for upgrade, did not cause me to not get anything I didn't already have, but some people on another board/group experienced missing files. So if you don't check it you may download stuff you already have but that is just more time to download and nothing else bad will happen.

My 2 cents anyway.

My wife asked if I had seen the dog bowl. I told her I didn't even know he could.