Has anybody fitted to a Discovery 2, LPG Gas Vapour Injection in the Sydney area?

I have an Airrod system and would like to know of others experience with the VI, is it worth it etc

I have just had the engine overhauled and it runs V well on gas, but if I could get a return on my investment with the VI, I do K30,000 per year, then I would seriously consider

+ I need it to be done by someone with experience of the D2's

Thanks