Remeber: This disc was 3.5 GB but DMGs are compressed, so its 2.91GB.
I ripped this (my own DVD) with disk utility, so its safe, for those of you who might be concerned. Also it does not need a serial number. Apple doesnt require those for any of its core products.

They assume youll buy them and they dont need to lock you down. ;-) But seriously though, if you like this you should consider buying it (not to get too preachy or anything).

You do not need to burn the .dmg file in order to install. Only do that if you want to back it up or install on a computer other than the one on which you downloaded it.