| I had an LPG conversion fitted to my Nissan Primera 2.0 litre when my mileage was heading towards 20,000 per year.
The tank took up most of the fairly sizeable boot. LPG filling stations were and still are few and far between meaning I often had to drive out of my way to get some gas. However, during the fuel duty strike a few years ago, I was fine because I could still fill up at household LPG depots that supplied Autogas.
I think the car ran a little quieter on LPG but it certainly had less power and worse fuel economy. LPG has a lower calorific value per litre. I had previously regarded the Nissan Primera with its chain cam engine as bullet proof but the car became unreliable after a couple of years on LPG.
Most irritating of all, the LPG supply system took no account of other demands on the engine. You just take it for granted that the engine management system knows to increase the idling speed when the aircon is used: with LPG, the car often stalls.
Still, having got some value from my LPG Primera, I decided to replace it with something more fun in 2003 - a MINI Cooper S! I now have a Dooper which is almost as good but 40 bhp short of power.
So, my advice would be only buy a dualfuel car if it is made by the manufacturer and just enjoy the Dooper  | 
