I was getting quoted around the $6000 mark to have lpg fitted to my L322 Range Rover - that was for the Prinz system that has been used well on them in Europe. Presume the same system would likely work well on the D3 too.
No option for a rear wheel carrier on the L322 though so would mean losing the spare wheel and at that price it would take a very very very very long time for any cost benefit to become apparent so really isn't worth it.
