I don't know specifically about AU1s but my AU3 ex-cop car has OPT20 on the compliance plate and includes the following:
- Lowered suspension (XR6 height apparently)
- No speed limiter
- shift points for auto at redline
- 240 kmh speedo at 2kmh increments
- speedo calibration function
- Interior light kill switch
- LSD
- lots of disconnected wire ing connectors
- holes in various interior body locations
- disabled horn and hazard flasher from smartlock (this was reenabled by reconnecting 2 cut wires from
BEM module under dash)
- cruise control and rear power windows (don't know if this is part of OPT20)
- lots of biro marks on interior