If you think you might one day do this again, do not use the whole glued area, unless you want to go through the (excruciating) process of removing the battery again.

Just went through this procedure the second time about 3 years after I did this the first time. When I installed the first replacement battery, I only used ~15-20% of the glued area on the battery to "loosely" stick it to the macbook body and placed some small foam pieces at the top (between the battery and the bottom cover) to help hold the battery in place. Had no problem using the macbook or with the battery, and what I had done in the first replacement made my second run extremely easier.

When assembling this back, one should note that the trackpad actually has some wiggle room in its slot, so it should be properly centered before firmly screwing down all 10 screws.

For me, adjusting the position of the trackpad and screwing the two red ones first while holding the bottom plate up at 90 degrees helped.

Just went through this procedure the second time about 3 years after I did this the first time. Didn't have to remove the motherboard, both times, like others said.

What made my second run extremely easier was not having glued the battery completely to the macbook body when I did this job the first time, as getting the original one off was excruciatingly painful and I didn't want to repeat that. When I installed the first replacement battery, I only used ~15-20% of the glued area on the battery to "loosely" stick it to the macbook body and placed some small foam pieces at the top (between the battery and the bottom cover) to help hold the battery in place. Had no problem with the battery (until it intrinsically went bad and I had to replace it today, of course).

(Translation for myself and others; Thanks for the nice tip by the way!) This is not a plug but a contact plate that only needs to be lifted slightly. Then it is best to isolate with some scotch tape.