I have just recentley had my L322 Range Rover converted,i am averaging 13 around town and upto 30 on a run....the fuel gauges that come with the LPG systems are not very acurate,i need to fill it up and run it right out to get a more positive figure....if you convert to LPG then get the biggest tank possible as you lose upto 20% filling capacity due to expansion,i have a 88 litre tank but i've never run it dry so i have never been able to get more than 50 litres into it......for 50 ltrs i did 150 miles.