After lots of research, finally I took a decision to for Fitting CNG Kit for my santro. I discussed with many dealers and revealed that there are lots of cheap(China made, which r risky) kits available in market, along with good kits. I would suggest never to go for these kits to save little money.
I fitted Closed circuit Lovato Kit from Gasoline Fuel System, Warje, Pune and am very happy with the performance till date. I was getting 14-15 mileage per litre for my car. Today I get 20-22. km per kg in city and 25 on highways. Also CNG is almost half the price of petrol. So the costing was Rs. 5 per km with petrol and currently it is less than Rs. 2 per km with CNG. Almost 60% saving. Saving of Rs. 3 per km. It mean if I drive 10, 000 km with CNG, my investment of Rs. 30, 000 for kit will be refunded. I hope to do it in next 8-9 months time. After that, its only profit.
Apart from mileage, acceleration is also good and top speed of 100 -110 can be reached easily. Very attractive proposition. Please go for CNG. Petrol is only s*cking.