brother i knw that its not feasible to have a cng but i have to see my own pocket as well.... 
from where do u recommend to get my car checked, toyota motors wont be touching CNG as they deal in petrol matters only..
i mean they will tune my car on petrol only, i need to get my cng matter fixed as i drive my car mainly on CNG 
Toyota motors will charge me very high as i need to get my brakes checked, my car wheels are making some chuioooo noise when the car is running plus when i press the brake i can hear the voice of brakes...