OK, got around to reading all your mods, found a couple of small issues:

Elemental Resistance doesn't list Force Shields as a prerequisite.

Might be an idea to move the Modular Armour proviso in Powerful Build, put it at the end of the entry. As it reads just now, you could be forgiven for thinking that this also applies to the Modular Armour;
This does not improve the Iron Man's reach, nor does it cause him to take up more space, nor does he take size bonuses or penalties to attributes or attack roll penalties for his size.
More a note for clarification, but would make it read easier if this appeared before mentioning Modular Armour.

Might wanna consider making Extremis a requirement for Remote Summons, in addition to Repulsor Flight, due to the self donning thing (you don't even need to touch the armour for Remote Summons, making this a slightly better effect in itself). Only a suggestion though since I doubt it's much of an issue.

Stinger Rocket doesn't mention how many bays you may have, as it stands, you could indeed have infinity + 1 bays, and that's just silly
Figure it's an oversight, but since I don't know what you intended, may I suggest you consider offering this one as a base of maybe 3 bays, allowing for more by taking the same modification more than once..?

Otherwise, the class as a whole reads nicely and the chassis is solid, although if this were me, I would be tempted to make both Diplomacy and Bluff class skills, if only for chatting up women (or men) and talking your way out of (or into) trouble. These account for a large amount of Iron Man's out-of-combat options do they not?

As for power level, it's Tier 3. A REALLY bad build would produce a low Tier 3, and a carefully tweaked and optimised build could brush Tier 2's underbelly at a stretch because there is both shattering power and versatility, but would still be Tier 3.
That's not to say it isn't astonishingly capable of dealing out punishment in large doses, and the fact that you have multiple suits does give you a wide range of choices for your combat skillset, as long as you get some idea of what you're up against in a fight (and/or install Remote Summons on all reserve and 'special loadout' suits...)
Action economy looks good, glad to see a fair few swift and immediate action mods in there, didn't see any blatant abuses with that.

All in all, this looks good, and unless anyone manages to spot a horrific gaping flaw somewhere, I'll be using at least two of these (VERY different builds) as NPCs in my current campaign.