Cruise control on DBW car is done through the ECU so it involves several things to change the max cruise speed limit. There seemed to be some filter/mapping used in order to prevent sudden change in speed or hunting so I don't think it will be a simple task compared to the non-DBW model.

For the non-DBW model, cruise control is calculated inside the control unit behind the glove box and it simply controls the actuator in front of the Brake master cyl.
On JDM model, the logic for the max cruise control speed can be changed.
I don't know how fast it can go as I don't have access to the rolling road but it's working on my JDM non-DBW NSX.

Not much help for you.....


Kaz