Keep track of screws is all you need to be worried about.
Also the Brown ZIF connector (Is a cable that connects the DVD drive to the Wii/not the white power cable but the other cable) is very troublesome. If you break that connection, your going to have to solder in a new one otherwise you will have a Wii that cant play any Gamecube/Wii games.
If you follow all of the instructions in whatever case mod you go for, you will end up with something like my Wii: