I can hear my music
After only 4 years of frequent use, the left fan on my Macbook Pro had gotten really noisy.
Every step was exactly as described by iFixit, right down to the difficulty in releasing the plastic clips over the DVD drive.
As noted in the text, re-engaging the plastic clips over the DVD drive is very difficult. Partially inserting a CD in the drive slot helps to hold the slot open so that the clips can be pressed hard enough to engage.