If you have the non-m bumper than yes you'll need the M-sport bumper to fit that diffuser.
Also like mentioned above whoever cut that diffuser did a terrible job and I would not pay for that diffuser. But that's not the diffuser's fault, looks like this person bought the after market quad diffuser already and it was not compatible with GThaus, that's why it was cut that way and looks wide.
GThaus quad was design for the stock m sport diffuser (flat surface)
You can use this to cut the openings for it yourself on either non m or the m sport.
https://www.kiesmotorsports.com/prod...16739476340851