@farazahmed dear.i also have 2003 model platz, but its manual tranny. i have a 60 kg cylinder in it and it gives me 200 km average within the city. i also got the cng fitted in it from lahore. u can go to that guy for tuning. name is Italian CNG. from kalma chowk, go on qasoor road, and on 2nd traffic signal, get the side road onto ur left. go parallel to the main road and u wud see the shop. rizwan is the guy over there who is the owner, and waris is the mechanic. they are outstanding in their job. give them my reference and Inshallah they will solve ur problem. u can also contact me at 03225579422 for any furhter clarifications. as for the road clearnace, DONT go for spacers and shocks as they will ruin ur ride comfort. go for 185/13s. i dont recommend 14s in platz as they are too big for the car and grossly affect ur car odometer reading
MOD EDIT: PLEASE write Inshallah, Allah, etc. with capital beginnings. fixed now.