I'm guessing that as they are 650MB movies, they will be DivX, which is quite well compressed as they are.
But i agree that WinRaring them on maximum will bring them down a little, but i doubt anything too substantial. Each will fit onto a CD, or will only take a couple of minutes to transfer, even over a 10mbps network! (i know, i've done it with about 15 movies, took about an hour to copy them all across a 10mbps hub! :Q)
ConfusedBW