Unless it's got a V8 supercar style rear diff with unis you cant adjust the rear camber.
It'd be scrubbing the tyres on the rubber mould thingy in the rear arch that EF/ELs have.
You could get the current springs reset a bit higher to raise it.

Search here and on AFF for posts by TurboTaxi. He has an AU turbo with a mixer-ring LPG system, has done 60.000+ km with this setup. Turbo or S/C mixer-ring systems can be done, there just aren't many gas fitters with the experience and knowledge to set them up.

Other than mixer-ring systems or SVI, you could look at GRA or Impco systems at a price between the other 2 options. As you're in Melbourne it might be worthwhile to ask Anthony at AM Autogas (?) in Wantirna South for his advice.