Water injection worth it?

[Arthur]

If you are just using water injection for cooling then you will not see much if any power gain, from my experience I did notice a difference in the summer where there was no drop off in performance due to high inlet temps.

To get the most out of it I suggest you get the water injection mapped via a Unichip or similar this way you will really feel the difference.

P.S. Why are you running a GT28RS at only 0.9 bar, I didnt think they were in their efficiency island until 1.4?