Stacking fire resist has been a hot topic. (pun not intended)

Pupu has done extensive testing relating to status resists and i highly recommend taking a look at what results he has currently. He and Eek5 also found a fun (FOV self inflicted damage is AFFECTED by sword damage bonuses)
http://forums.spiralknights.com/en/node/10522

Whereas Zeenzie has asked a GM for a answer on max fire resist on vog which you can find here as well.
http://forums.spiralknights.com/en/node/16171

Now from my personal experience (which is unreliable, biased and random) having seen a fellow guild mate prancing around in the licking flames that surround Firestorm Citadel with a max fire resist vog has demonstrated to me that there is a clear difference between a normal vog and a fire max vog. How clear is that difference is still up for grabs. But after seeing him walk through firesnakes fire traps and fire based attacks, I have followed his path and also made a fire resist max vog quite recently to my utter delight.

fun things that I have noticed so far.

In the advanced training hall with normal vog SET briefly running through the fire trap [4 secs of fire no visible damage] if stayed in the fire trap [4 secs of fire half bar damage]
In the advanced training hall with one normal vog COATand one fire MAX resist vog cub Cap briefly running through the fire trap [no fire no visible damage] if stayed in the fire trap [no fire half bar damage]
in the advanced training hall with one normal skolver COAT and one normal vog CAP briefly running through the fire trap [5 secs of fire no visible damage] if stayed in the fire [5 secs of fire half bar damage]
in the advanced training hall with one normal skolver COAT and one fire MAX resist vog cub CAP briefly running through the fire trap [no fire no visible damage] if stayed in the fire [no fire half bar damage]

what this shows is...the advanced training hall is a terrible place to test stuff. I'll let you know what happens when I go fight Vanaduke again.