El Güero, as for the Lambda Sensor, there is no need to remove it as it is in the front part of the exhaust:
(Item no 13 from this diagram)
I know that some people removed it and there is an eliminator for this job.
I will have to check if they put the eliminator in place but I know that there is one thing that has to be done, and was done on my bike too, which is the exhaust valve servo.
It is operated by two cables and you can either disconnect cables driving it and leave the servo motor in place or buy an eliminator.
Again I am not sure what was done on my bike but I will check.
One thing is that they've done something to the ECU, I will ask if it was just a flash/reset or if they've remapped it. I have the ECU report and it has Lambda readings so I am assuming that they have not removed it.
All that stuff was done as a part of the major service but I know they put 0.5h as fitting service charge and the exhaust was provided by them for four hundred. You can get it cheaper on sportsbikeshop.com but it takes 4 weeks to deliver.
I will be washing the bike on Saturday so I will check whether any Lambda or Servo eliminators were fitted.
Just to reiterate the sound of this exhaust is epic. I've heard LeoVince, Shark DSX1, and Fuel on MK2 but having the Remus before I knew that you pay a bit more for it but it is a proper thing. I've had older Remus on my previous CBF but this one is improved and it sounds much better.