One of my friend has a 07 prosematic reborn on CNG. It runs excellently. The milage (55 cylinder) is also very good: 120 - 130km (within city) and 150 - 160km (long route). I live in Islamabad, if you were here, I would have definitely recommended his CNG workshop for you. But in Lahore I have no idea. Unless you wanna come and get it installed here.. lolz...
I just recently bought 2010 Civic but I have decided to keep it on petrol for atleast 50k (untill Warranty expires). Then I would definitely go for a CNG. Honda has already launched a CNG vehicle in US called NGV (natural gas vehicle). you can check out the car on youtube.
I would recommend 55 cylinder, Landi Renzo Kit with PVR emulator and advancer for your car. It will be more than best if you go for Lambada system. That would save the life of your engine and dramatically enhance your performace. Total cost of this mission would be 43,000 (without Lambada) and 58,000 (with Lambada).
Choice is yours bro. Email me if you need any additional Info.
Cheers