Go to ftfs at faisal town. Its close to your place. U just need a 55litre cylinder or 60litre if u want to, a kit preferably landi renzo italy with big regulator (not the small one), dont go for landi renzo brazilian, its about 2k less but cheaper in quality, an emulater and a timing advancer, thats it. If u want u can get the lambda o2 sensor installed but in my opinion u can do good without lambda.
u l feel about 25 percent loss in power in auto tranny but u l get used to it.
u can check rates from kandan tøo and compare with ftfs. Installing cng in prosmatic is no big deal. Almost every workshop is doing it.
Make sure they do not drill any hole in the trunk.