Saw the 54 Bit driver kit on TWiT and wanted it right then.
Didn't have anything that needed fixing other than the need for a nice set of screwdrivers. I did add some RAM to my parents Mac Mini not long ago...
Thanks to the kit I bought from iFixIt for just that purpose, the process of adding that RAM to that Mac Mini went very smooth.
If for any reason I need to replace the glass on my iPhone 4 or do any other work on that Mac Mini, iFixIt is the only place to go to find out just how to do it.