I would like to congratulate you on a mod that is awesome, not OP and combines all the useful items from other mods into one package! I made the Jetpack module and the Jetpack for the boots(can't remember the name) and discovered that they are extremely hard to craft! Ion Thrusters, 2 of them take 1 stack of iron? Could you maybe tone the recipes down a little, like using cable in stead of Solenoids?
EDIT: The IC2 jetpack is WAY easier to craft, think about that!
I would rather strongly disagree with this. The IC2 jetpack isn't also armor, isn't also an energy storage device for other items, and isn't a whole bunch of other things as well. Quite bluntly, when you get done with MPS, it's effectively Gravisuite. I think the costs are nicely balanced.
As far as ideas for the mod:
NBC Shielding: helm slot upgrade. Requires: a LOT. Like maybe 4x force field emitters plus some other stuff.
"This upgrade will create an environmental seal, enabling you to enter hostile environments without suffering any negative effect. It is, however, draining on your batteries."
In effect, it prevents negative potion effects from affecting you. Hence why it requires four items that in turn require multiple diamonds, as well as a whole host of other stuff. In effect, Qsuit helm.