Thanks everyone for your replies.
There are several reasons I bought the Non-CNG variant:
1. First the price difference between a cng and non-cng Alto
2. Since this is a leased car, I would be paying lease on the CNG kit and in the end that would have cost me around 80 to 90K. If I want I can get the kit installed from the market for <35.
3. I don't have to drive much, it is only 20kms/per day for me, if I had to drive more, I would definitely get the CNG kit.
4. This is my second car, so I still have another car to go on.
Well, I will upload more pics later, as I have got the mud-flaps & seat covers fitted. I have only driven < 100kms and I am enjoying the drive.