I used to have a Grand Cherokee with an LPG conversion and loved it the only downside is the time taken to fill the tank is longer than petrol (not nice on winter days). I probably compounded this issue since I had a smaller than normal tank as I did not want the rear floor raised. This caused me to go to the filling station about every five to six days.

One other thing I did discover was the conversion did not help with re-sale value but the conversion easily paid for itself. I used to get 16-17mpg on petrol and the equiv of 32mpg on LPG!

Now I have the X5 3.0D and yes LPG conversions can be applied to desiel cars but it is a much more expensive install.