waleed_mabood14, i have used Toyota Platz 2004 M/T 1.0cc has same vitz engine... it had tomasto kit and 55kg cyclinder it used to go 120km with a/c and 150km without a/c in Karachi, my personal experience for 1 year... and driving m/t platz n vitz is fun ! u won't feeel much power loss on cng! For vitz 50kg might be suitable..!