Newbie with a supercharged monaro

[leedpm]

hi all,
I?m running a 04 monaro vxr with an intercooled Magnacharger 9psi 2 bar mafless tune with 440rwhp.
As I?m a newbie to water injection I no that the engine will benefit from it once it has had a custom tune, but can anyone tell me a rough guide to the gains it will achieve, and is it really worth it.

Cheers.