MOSTLY PEOPLE PREFER FACTORY FITTED CNG. BUT IF CNG IS MANUAL FITTED FROM A GOOD TECNICIAN THEN IT IS ALSO OK. NOT TOO MUCH DIFFERENCE IN PERFORMANCE ONLY FITTING STYLE DIFFER. LIKE IN SANTRO FACTORY FITTED IS GOOD AS ITS CYLYNDERS DONT SHOWN AND FIT INSIDE THE BODY, BUT IF IT WILL BE MANUAL THEN CYLINDERS WILL BE VISIBLE AND SMALL BACK SPACE WILL BE LEFT FOR LUGGAGE.
FACTORY FITTED COMES IN WARRANTEE BUT MANUAL INSTALLED CNG VOID WARRANTTEE OF ENGINE.
ANUWAY, I JUST HAVE BOUGHT A COURE CX AND INSTALLED MANUAL CNG CYLINDE OF 55. IT IS APPLIED FOR YET.