ima preety sure armor (as odd as it seems) protects the shields as well... but i am not 100% on that.
and its best to nano (egg?) things while the shields are still full... so you kill that annoying illum with full shields left. teehee.
anyway... every armor reduces damage 5% through a wierd formula that the game uses for many things...
heres some baselines...
2 armor reduces damage 10%... so it takes 91% of normal damage. (multiply .9111 times 1.10 to get 100%)
5 armor reduces damage 25%... so it takes 80% of normal damage (multiply .80 times 1.25 to get 100%)
10 armor reduces damage 50%... so it takes 66% of normal damage. (multiply .6666 times 1.5 to get 100%)
20 armor reduces damage 100%... so something would take 1/2 the damage it normally would.
30 armor (only a tricked out space turnip can get this) reduces damage 150%... so it takes 40% of what it normally would.
yes... that means a orkey... gets 60% damage reduction from shields and 60% damage reduction from armor... for a total of 24% damage actually taken... throw in a phasic trap (hanger bay) and you got something that will take a serious beating.