What are the best lpg systems that would be the best on an ed falcon xr6?
been told there is different type systems out in the market.thanks in advance

It really comes down to how much you want to spend. Since you're in WA, the rebate will offset $3000 anyway, so that will give you more leverage.

According to most, if you are chasing the most power and economy, injection is the way to go. I have seen kits for around $4-5000.

Personally, I have a standard OMVL mixer setup, and for $2900 it is pretty good, ~500km to 68 litres on the freeway, and perfect idle etc...

Thanks champ.so there is an injection type which is obviously better and a standard system.what are the differences between them both?i might need to know if i ring up places for quotes and i want to know what i am talking about

There's two basic types on the market. "mixer ring" type and gas injection.

The difference between the two is similar to the difference between carby and fuel injection.
gas injection is computer controlled and gives better economy and more power, but more complexity means higher initial cost.

Another alternative is gas research system which is a variation on the mixer ring setup, this is somewhat of a compromise, as generally economy is slightly worse than a good mixer ring but power is increased.
Gas research will cost around $3500 which puts it neatly between the other two in terms of price.

I initially went mixer ring and there was a noticable power drop, I would say around 20% over petrol, I have recently had gas reaseach installed and it now feels just as good as petrol.

By the look of your sig you'll definately want either gas research or injection.