Just Drop the MaxPowerBoost Folder into your scripts folder and your good to go.

default controls are 

MaxPower         = PageDown
Traffic On/Off   = PageUp
SpeedBoost       = LShiftKey
FixVehicle       = Delete 

but you can change them in the   Config file

gamepad controls are

MaxPower         = RB + RS
Traffic On/Off   = RB + A
SpeedBoost       = RT + A

When MaxPower is on it works with any Vehicle including flying Vehicles.
have fun...