Can I convert my Nissan Murano to LPG?

Is there any problem in converting my 2005 Nissan Murano 3.5L CVT to run on LPG? I have heard that the valve seats could wear prematurely - can this be avoided? If OK, what system would you recommend?

Which SUV could I replace my Nissan Murano with which will be cheaper to run?

I have a 4-year-old sports utility, a Nissan Murano, but running it is breaking the bank as it only does 20 miles to the gallon and road tax is a mind-boggling £445 a year. The size is perfect to the inch....