I looked into this years ago. Doing it will require a full chassis wiring harness from a 325 which came with the full check panel. The harness from the panel is hard-tied into the chassis harness, and there are various little relay modules which install all over the chassis to detect light bulb failures and whatnot. Trying to splice it in would be even more difficult than gutting the car to pull the harness. So, it would be an ENORMOUS job. Also, you'd need to do some custom work to install oil & coolant level sensors.
If you are really good with electronics, you could design a new PCB for it that uses a microcontroller or other solid-state logic, and thread new current sensing lines through the chassis to get the same functionality. But, you probably need an EE degree or equivalent experience to pull that off.