Cars Q&A

I own a Hyundai Sonata GOld-2002 Model, around 62K Kms Run, My problem is the Mileage issue, company claimed 9 Kms /L where as I am not getting more than 6.5 Kms /L ( with AC), & because of that my friends are suggesting me to put Gas Kit to my car, Further i have tried to collect info about the same, but i did not get any proper inputs. I have some questions regarding the Gas kits. 1. I heard that new generation, direct injection type Gas kits are newly launched for Big cars, which will not even make feel that the car is running on gas as they are claiming that there is no compromise with the Pick up & also the mileage /KG will also increase , is it true? 2. Due to LPG operation, does the car value will reduce the Healthiness of the Engine & Life too? 3. The valuation of the car is going to be reduced due to gas fitting? 4. What is the approximate cost of fitting the Gas kit? Also request you to plz let me know some good dealers who fit Gas kits to big cars in Bangalore to my mail id swapnil_natu@yahoo.co.in. Also I request all Sonata owners who are running their cars on LPG, plz plz mail me your experience.......