I would copy the bak file over and restore locally - I doubt there is much difference in the new traffic to do this once - but it means you can restore the bak multiple times to the test box without further load. Copying the bak over the network will saturate the lan connection on the prod box - making all other clients slower - so if it is an option I would recommend copying to e.g. a USB drive on the server then walking that to the test box ... watch out for USB weirdnes though - if you test box is similar config make sure the drive works on that OK before plugging into prod