Answer to your queries
1- The car should be comfortable and have a good driving experience(Important).
Both city and swift are fun to drive.But i personally like swift in terms of handling,brakes and road grip.
Where as city is more comfy
But if i would be in your place i'll never buy both cars and try to find unregistered 4.5 grade 08 VITZ 1.3 ltr almost same price of new swift.
2- As i have already stated i am a student and keeping the car on petrol is not economically feasible for me, the car has to be converted to CNG later after the purchase. So i need to know which car runs better on CNG (City vs Swift)
Honestly none of them are designed to run on CNG and I dont know y PPL install CNG when engine is more electronic and only engineered for petrol as source of energy.
If you are planning to keep car for long time i wouldn't reckon CNG.
Anyways less issues are recorded for CNG with city ivtec engine as compared to swift DOCH engine.If CNG is must then coure/cultus are best fit.
from my personal experience CNG saves you some money but in the end u'll be spending more on maintenance.I guess city if driven with normal rpm gives 14 km /ltr
Assume full tank of CNG gives 140 km and your cylinder capacity is 9 kilos
Cost:4.14 rs / km
If you are getting 14 km ltr then cost would be:6.35 rs / km
If your daily mileage is 30 km then 190 rs/day for petrol
If your daily mileage is 30 km then 124 rs/day for CNG
At the end of month u'll save 2000 rs but you've to wait in long queues,secondly car running on CNG would require oil/filter change earlier and engine life also effected.
3- The resale value should be acceptable as i will have to sale the car one day.
City all the way then
4- As CNG is only available half the week here in Lahore, my car will have to run on petrol too. So which car gives a better mileage on petrol is also a concern. As per my knowledge, on petrol City has a better mileage than Swift. Correct me if i am wrong.
City has much better average as compared to swift.
Suggetion:Also Consider Passo 1.3 it can run on CNG and cost would be less than swift and drive would be 1000 times better than alto and cultus.