CNG will ruin a 660cc engine+
pick up quality will die as in patrol also its average
its average is better on patrol, so y do you wanna convert it into CNG, be sure that if u put a cng in it, you are ruining your car as well as adding a considerable weight of cylinder into your car, making it difficult to run a 660cc engine with passenger load, & your car will do like
plus after some time your car will start making mechanical works, but also depends on how you use your car..
Itnay disadvantages kafi hain ya aur..