hi, welcome to TAI
. as you said your yearly running is 8000-10000, i don't think you will need a diesel. by the way, ciaz petrol is good in city traffic, also good for highway. but not that good as the other cars of its segment. i have driven the petrol version. but haven't drive the diesel yet. why don't you consider the fiat linea and honda city? their petrol engines are superb.