I installed CNG after 42K driving on Petrol and still drove 3 days on Petrol every week due to load managment schedule. So, i never forgot the smooth feeling of the petrol. But, due to CNG installation never got any good consumption on the Petrol infact if i cover 1000km in total, 50% was on CNG and 50% on petrol. Also, i was getting petrol aveage around 10kmpl. That is why i removed the CNG kit at 85k and now i m happy and tension free. My average consumption is around 18kmpl and costing me only petrol thankfully no extra load of CNG cylinder.
For me CNG never worked good once it crossed 55 PKR barrier. Now its neither cost effective nor good for car in long run(keep in mind i m talking only about i-DSI since average consumption for other cars is way too much )
BTW..............which porsche model u made today??