Anyone convert their engine to CNG (compressed natural gas)?

If so, what are the pros cons. How much fuel savings have you enjoyed. Have you regretted it?

DRAWBACKS OF CNG…according to wiki

Compressed natural gas vehicles require a greater amount of space for fuel storage than conventional gasoline power vehicles. Since it is a compressed gas, rather than a liquid like gasoline, CNG takes up more space for each GGE (Gallon of Gas Equivalent). Therefore, the tanks used to store the CNG usually take up additional space in the trunk of a car or bed of a pickup truck which runs on CNG. This problem is solved in factory-built CNG vehicles that install the tanks under the body of the vehicle, thanks to a more rational disposition of components, leaving the trunk free (eg. Fiat Multipla, New Fiat Panda, Volkswagen Touran Ecofuel,Chevy Taxi (sold in countries such as Peru) etc). While CNG-powered vehicles are considered to be safer than gasoline-powered vehicles [2][3], there are concerns about how best to fight fires involving CNG vehicles.[4] Since its calorific value is far less than other fuels it needs comparatively large volume of Gas to get desired energy.

wiki

Troy Liposec purchased an older ('96?) Ford Econoline with CNG.

Contact him for feedback.