This vehicle does not need more power. Top speed and acceleration are not the car's purpose; off-roading is. And the only thing it needs the adapted suspension, and lots of torque, which it has from the diesel engine.
"the speed limit is 70 MPH and in some areas, the police allow you to drive up to 10 MPH over the posted speed limit."
Here, it is pretty much the same. You don't need to go exactly below the indicating speed limit. You can exceed another 20 kph, and the police won't fine you. But even if you totally exceeded the speed limit, beyond the permissible, and police stopped you - your money would make all the deal, and you're free.