Not sure what figures would be seen if manis are fitted, still guess around 200 maybe a little more, each car is different. Economy will improve slightly but will only be noticed when driven sensibly!
It will also be a little smoother. It won't be noticed straight off as most will be experiencing placebo when driving home, it's a natural thing. Over time you will notice the difference when things settle down and the novelty has worn off when fed up visiting the pumps!