If you are completely stripping the machine down, which you will need to do in order to replace the top case unit, you will need the following:
- T8 Torx (for the display and display bracket)
- #00 Philips (i prefer a #000 for more precision, just be careful you dont strip the screws)
- T6 Torx (to remove the trackpad click adjustment screw)
- Tri-Lobe #0 (to remove the battery)
I would also have a piece of paper or a sticky note that you can rip up for when you fit the trackpad, as i put a piece against each of the 4 sides to make sure its aligned properly in the middle...
Make sure you wear an anti-static wrist strap when working on this, as you need to remove the logic board in the process!
be careful and have fun, its easier than you think to blow a logic board... make sure the battery is disconnected first and you give the board a chance to drain properly before handling it too.