First of all, this is Toyota "Corsa". Not "Crosa"
1. 13.5 to 14.5
2. It doesn't have good market as "Corolla". But good, Japan manufactured, Domestic car.
Corsa is a separate platform from Corolla by Toyota. car is not bad on Fuel. It's not a too Heavy, Big car.
3. * Corsa diesel has "Tourbo" engine. Make sure Turbo is on by listening to "Beee" sound.
* Do common inspections like, Engine oil Condition(So that Engine is good), Transmission oil(If automatic) and that's all.
Overall, good car to have specially as day-To-day runner.