crdi

hi , i am thinking of buying used hyundai accent . i have these options 1.accent petrol with lpg for 1.3k 180000 mileage done 2000 model. 2.accent crdi diesel 48000 to 100000 mileage 3.or should i get accent petrol within 1.2 and convert it to cng ? what u think about it ? what will...