Choosing between a CNG kit and an LPG kit depends on your needs and niche requirements. Where CNG kits are concerned, they have one huge disadvantage. They just take up a huge amount of luggage space and generally have to be placed in the boot of the car. Also, their exteriors have to be made of sturdy steel capable of tackling the wear and tear of rough cross-country drives. Each conversion kit can cost anywhere between Rs 25,000 to Rs 35,000, which should be recovered from fuel savings in the long run. That said, reports suggest that CNG may slightly hamper vehicle performance as compared to LPG.