I agree with your analysis but they do state they are using a powerful lens to even get that footage and then further on....

3:20ish "We're having trouble keeping up with this guy"

3:30 "We are currently going 120MPG and he is losing us. We're at the maximum speed right now." [news anchor after speaking to pilot]

3:50 "This is the first time the vehicle has outrun the chopper" [studio host?]

So I think you are correct in the 130-145 MPH max speed and them just hitting 120 due to wind or hardware.