Blind spot monitoring retrofit for a facelift Mercedes GLC

Good afternoon. I am trying to retrofit blind spot monitoring to my facelift Mercedes GLC C253 from November 2019. It already has the MBUX NTG 6.0 system (VIN WDC2533161F692205). I have already bought all the necessary parts: the radar sensors, their brackets, the bumper wiring, the mirrors with the red triangle warning LED, and the door modules, since my current modules are not compatible with this retrofit. I need help with the coding. I have Monaco DTS 8.16 with an OpenPort 2.0 interface and Xentry version 2025. I will not install it until I have the coding. By the way, can I use second-hand radar sensors and door modules, for example from eBay, or do they have to be new? Thank you very much.