For example, being able to register custom upgrades that are better than the Highly Advanced Machine Upgrade but inferior to the Quantum Upgrade. For example, an "Elite Machine Upgrade" which gives +512 EU/t max overclock.

There could also be upgrades that only work in specific machines. Example such upgrade: "Advanced Furnace Upgrade" which gives +168EU/t max overclock (total 200 EU/t) but only works in the Electric Furnace.

Message with original suggestion: https://discord.com/channels/754461970870173767/760125612126896196/1096886610739609671