how to check if tampered?
my experience during working with toyota some years back, there are several times ppl planning to buy a used vios/altis/camry - they came to my service centre and ask what is the last service record.
if they were lucky, previous owner had full service history before selling the car and we will know what would be the actual like. normally, and not surprisingly the odometer will be tampered to show something like average 15K km per year when previous owner was doing like 30K a year.
the usual tricks, alter the odometer, wash engine clean and give a new layer of paint and voila - salesman will say this car is low mileage, no accident, tip top.. bla bla blah! ha ha ha...
not so good if previous owner had long stopped maintaining his car with authorised dealers. i think it is time already malaysians open up their eyes and walk away if the car is not maintained by appointed dealers but pokok cherry workshop.