Well if you aren't worried about it still turing on, all you would really need is a dremel, and your normal tools like screw drivers, and of course a sledge hammer if you get frustrated!

So you just want to place an external drive in the Mac? Just make a whole from the wire to come out and you might want a small computer fan, heck you could probably wire that into the Macs power supply, with some diodes and the like. (Or a small battery, your choice.) Do you want the drives powered from it as well?