our liana was driven 200000 plus when we swapped the engine. The coil problem started for no apparent reason. It destroyed 6 coils in a mere 3 months thus we decided to better get rid of the engine.
The swap was a complete engine + 5spd gear + Ecu. The M18 was a VVT as far as I remember. And the whole swap was dirt cheap too.
Edit: I dont understand what you mean by local CNG since there isnt any imported CNG and all cars run on the same CNG. However, we drive our cars mostly on petrol. From the 2lakh km's the car was driven before the swap, i would say it covered a maximum of 30k on CNG. the rest was all petrol.