If you find the port of the oil pressure switch that is already there, then add an adapter to it and the "new" pressure sensor.
You can use an electronic remote reading sender unit and gauge or a direct reading gauge unit.
On the top of my head I'm not sure where the current pressure switch is.
Let me look tonight and I'll get back to you.
This is far simpler than drilling and tapping and fitting and sealing. It also worked a treat on my E12 M30B3.5.
Cristian