Has any one done this?

looking at it for more on the cleaning carbon side but would also be in it for some HP...

 

Your justa is port injected meaning the fuel is injected in the intake manifold which washes the intake valves so you shouldn't need it...waste of money in my opinion. The S models have direct injection which injects the fuel into the combustion chamber so there isn't any fuel in the intake to wash the valves which leads to carbon build up.