It seems that an entire clip of SCARAB will bring a max user down though...so 25x30 (assuming I missed 20 - this was back when extended mags was 50) = 750 so maybe about 0.2x damage multiplier?
Maximum Nanosuit upgrades your multiplayer suit from 1.5 to the singleplayer 2.0 suit...so your Armor mode is actually useful, but along with that you get infinite energy for a short period.
Yeah, I thought he answered your question well enough, considering how you posted it. Maybe "you" should be more detailed in asking what "you" want to know?
By default armor mode absorbes 35% of incoming damage. With max suit on that goes up to around 90% if my observations are correct. Also, you get unlimited energy while your in it. Your pretty much invincible so just throw on nanovision and see how many people you can kill in the short time you have it.