Looking at page 148 of the corebook. It says that if the modified DV of an attack does not exceed the armor value (This does not include your body rating?) then the damage is stun. Do you still get a chance to reduce the stun damage in some way?
Otherwise it seems more logical to go around with low armor rating. At least then you get to roll your body + armor to reduce the damage you take otherwise your taking the full damage in stun which still gives you the -1 for every 3 damage.