Well there's a 5th option however this one is a bit more expensive, requires a BSP adapter and wiring to adjust new values.
Haltech Bosch came out with a single physical sensor that reads temperature and pressure as well.
If the values can be adjusted via resistors it could technically work. In all reality the ECM would just need to see the same high oil temp voltages as the OEM. Under this condition it just serves as a monitor.
4 wires
$100-$130 sensor + connector
External Oil pressure monitoring device is required, it's possible that this same sensor can be connected to the A/C pressure switch or Evap pressure switch to display OIL PSI on ECUTEK.
