The Toyota Corolla has always demanded a good value in the used car market. The car model is known for its flawless running and good comfort level. You need to check on the car model you considering, get the car inspected at an Toyota workshop. Check for its service history, check all legal papers etc and tyre condition. Fitting an CNG or LPG kit is a good option provided you fit a reputed make and from an experienced LPG mechanic.
Yes you can get it installed. But we won't recommend it . Since, it will void warranty. CNG is best suited alternate fuel option instead of LPG. However, there are no CNG filling stations available in Faizabad UP. The nearest one is in Lucknow.
We would not recommend a CNG kit on Brio for it doesn't have a lot of low end torque in the first place and the kit makes it worse. On CNG, it will require a lot of throttle input to get it going in the first and second gear. Hence, we would not recommend you to get CNG kit fitted..