I have just done this repair now and it all went great with the help of this article. I purchased a second hand top case which had a battery, trackpad, keyboard, speakers and microphones still in tact and in good condition. This allows you to skip nearly 50% of the steps in this tutorial. Highly recommended to try and find something similar yourself. Slow and steady is definitely the way to do this repair and if you do that and use the right tools you will find the repair to be easy and painless. Best of luck to all.