vehicle grading is only for auctions for starters (so private cars and dealer cars wont have one). and basically by anyone smart it's only used as a guide to decide which cars are even worth looking at in person. never bid on or buy a car based only on the auction grading. any auction car needs a physical inspection. I have looked at cars in person that were 4 or 4.5 graded and they were rubbish. and I have seen some 4s that were awesome. a lot of stuff gets missed though. they don't bother too much with engine condition, underbody condition, brakes, suspension etc.