Sir he 2nd Gen Vitz launched (new shape) in 2005, its price is from 850K to 1000K, depending on equipment, mileage and condition.
Dealers will bargain 50-75K less depending on model, There are no changes between 2005-10 model, get the model with less mileage, good condition and more equipment.
I do not think there should be a fault in push start on CNG, if you install a good EFI SIS Kit.
You can also get a 2005-06 Belta for 950-1000K.
For Accidents a good mechanic can tell you about denting and mechanical work.