Not sure on RVR bro.. But since it is mitsu, you can check with proton. Normally they are compatible with a BIG price difference.
Last time I changed mine after diagnosis. I drive toyota corolla AE111. PRice form UMW, original is RM7XX. I checked myvi's one, RM190. It is the same type of sensor. 4 wire sonsor (one blue, one white, 2 black). But the mounting bracket is not the same. And this model's O2 sensor does not share with other cars. So a bit susah. But still can be done. My technician modified the mounting bracket. Just a little engineering work. Drill the holes on the bracket to fit the holes in the exhaust pipe.
If price too expensive for mitsu, try check for OEMs at Bosch or Denso. They have. You can even get Bosch wideband if they have for your car.