I analysed your idea and certainly have a few concerns,
 -> The papers which are provided during purchasing the car.has all the valid information that is buying date,Engine number which can't be altered.
-> Do you really need blokchain for that ?

-> The distance car has run in his course also couldn't be altered since the meter display the exact time from the day it was launched.The documents you get with the car have unique customer ID's which records are maintained with the insurgence companies and you can verify them online.

-> As long as exporting them,why would someone pay twice the price of an actual car just for shipping ?