Used HOLDEN COMMODORE VX EXECUTIVE 2001 - Victoria - CarPoint Australia
Here's one where you wouldnt have to install lpg. In the vx there seem to be quite a few already with lpg, and some with factory fit.
The earlier the lpg was installed the better, if you choose to go that way, as lpg is cleaner burning, so is nicer for the engine. I used to have a 02 vx exec factory lpg, and was up to 210,000kms and still going strong, ran really well on gas, and open road I would get 550-600kms out of an 80L tank.
In regards to an install, my ve was quoted at 4950 installed, for an injected system, but a vx you could have the older style system which taps into the air intake (not sure of actual name of it sorry), which should be cheaper, this system worked fine in my vx, it can sometimes cause a backfire that exits through the air intake box, but this is generally caused if you get a **** fill, similar to if you get crap petrol, your car wont run too flash, but other than clipping the air box closed again, thats about it.
The rebate is done through centrelink, you print a form off the net from the website, and then hand that in, to centrelink with the installer certificate, and they will give you the $2,000 rebate for the install, Ill be doing this when my install gets done soonish.
The only pro I thought I might mention in regards to getting a petrol vx and then doing the install, is you can opt for a doughnut tank in the spare wheel well, and retain the bootspace, where as the factory fit option is an 80l tank behind the back seat, so almost halves the bootspace.
Hope this helps you, if you need any more info just ask.