I hav SANTRO GV
What i get is
[highlight]Rs. 1.5 / km without AC in CITY driving.
Rs. 1.7 / km with AC in CITY driving.
Rs. 1.2 / km without AC on HIGHWAYS.
Rs. 1.4 / km with AC on HIGHWAYS.[/highlight]
Yet i m using STOCK SPARK PLUGS.
And i don't think so there is difference for getting the milage in GV and non-GV SANTRO like both hav same engines.
The BEAUTY of GV is actually the TRUNK SPACE after having 3 mini CYLINDERS.
And YES CNG KIT tuning does matter aswell.