yeah it has a massive effect on resale value,

they get put into the catergories by the insurance assesor depending on damge/cost/ and what areas are damaged,

i would imagen the cat b would be heafty chassis damage. cat a is normally fire damage etc

they have the catergories simply to allow people to have an idea of how bad the damage is, but legally it mean nothing at all.

the vic test is more involved on cat a and b cars, but i cant say why or how as im not allowed, i had to sign the official secrets act to do them and can get prosicuted if i tell you too much