[seasidebaz]

The instructions are on the website - disconnect the throttle signal cable and attach the box inline to the terminals, then fasten it into the footwell - but you can't do that easily in a Mazda

 

[seasidebaz]

Seems like it just tweaks down the signal sent from the accelerator pedal, i would say given the additional range figure somewhere around 10%

Would also be non-trivial to fit in a Mazda given the pedal is bottom-hinged, I think you have to remove the whole pedal to get to the sensor