Phillips Head Screw size in steps 8,23,24,25
The Phillips head screws in steps 8,23,24 & 25 require #0 Phillips screwdriver. Using #00 will strip the heads making them nearly impossible to remove.
I learned this the hard way in step #8 while trying to remove the 2 2.3mm screws holding the left fan in place. The rearmost screw stripped and I was only able to remove the logic board by removing the optical drive and the long screw holding the black bracket to the bottom of the case. This is the bracket that secures the optical drive on the left side, and the rearmost left fan screw. I was able to tilt the logic board sufficiently to work the logic board out with the left fan still attached with the remaining stripped screw. Once the logic board was out, I was able to remove the one remaining screw holding the black bracket down to the bottom of the case. That screw is under the logic board and inaccessible until the logic board is removed. I was then able to remove the left fan and remove the remaining stripped screw from the underside by tapping it with a punch to break the lock tight seal.
A jewelry #0 Phillips worked well for all of these 2.3mm screws mentioned in steps 8,23,24 & 25; but it is necessary to apply significant down pressure on the screwdriver by clamping a small vice grip to the handle and turning carefully. All of these small screws are secured with lock tight during assembly, so the it requires considerable down pressure to break the seal.
All of the remaining steps were accomplished without incident. However I recommend EXTREME CARE AND PATIENCE. My object in attempting this project was to replace the heat sinc compound due to overheating.
Work slowly and carefully, following the written and visual steps exactly. Disassembly (with the stripped screw problem) took me about 4 hours.