Yeah I didn't mention the spring because it seemed a little obvious since it won't do anything with the lid open.
if you plan on swapping instead of modding, another thing to keep in mind is that you want your original disc to have as many audio tracks as possible, if your game uses redbook audio. It seems that when the TOC is scanned on the original it notes how many tracks the disc has, and if your burnt disk tries to play redbook audio on a track number higher than the source has, it will fail to play. I might be getting some of the details incorrect, as it's probably been 10-12 years since I did it.