@Faisal
my friend In suzuki liana 1.6 CNG working fine there is no issue you can convert from any cng conversion center as shown up your city is lahore you can contact on this number #
(Ahmed CNG 0300-4580332, 5271267,Mr Amanat.)
(Mverick Petrogrs 0300-5400001, 5202526, Mr Imran.)