You can upgrade or replace the following parts:
* The M2 SSD (1 TB+ should be supported - watch out for BIOS updates)
* The battery
* The non-soldered RAM (up to 16 GB) which adds up to 20 GB total
* The WiFi card
As you can see at least your data will be accessible if your motherboard becomes faulty. [br]
Adding a 8 GB stick of RAM and maybe a larger SSD may be a good upgrade depending on the model.