Thanks a lot, this was exactly what I was looking for. Was already planning to write my own version of this, now I don't have to :) . This will keep my marathon-mode mega-base busy for a long time.

One minor question: how did you come up with the values in the recipes? Most seem natural (like doubling crafting time each step). But the red/blue circuit inputs look quite random (vanilla has 5+5. You have 8+6, 11+8, 14+9). Works totally fine the way it is, I'm just curious^^

You're welcome! I made this because my friend wanted me to... don't tell him I told you this but he doesn't have a great eye for balance. Off topic, but I actually would have done efficiency modules as well but making the sprites was much more work than I thought it'd be and I didn't see a huge need when e3 modules already are so great.
I came up with the recipes by making a completely arbitrary equation loosely based on the vanilla module recipes; here's the snippet of code that reflects that:

        {"productivity-module-"..(tier-1), 4},
        {"advanced-circuit", 5 + 3 * (tier- 3)},
        {"processing-unit", 5 + math.floor(1.5 * (tier- 3)) }

So yeah it's kinda awkward. I probably should have stuck with the 5+5 setup.

Off-topic again, but here's a snippet from the code that determines how powerful each module was. I'm thinking of making productivity significantly more powerful if I am to keep the absurd costs. My friend argued that, despite the inordinate cost, it would still be unbalanced to give the allrounder any more powerful traits.
productivity = {bonus = 0.06 + 0.02 * (tier-1)},
consumption = {bonus = 0.4 + 0.2 * (tier-1)},
pollution = {bonus = 0.05 + 0.025 * (tier-1)},

You're welcome! I made this because my friend wanted me to... don't tell him I told you this but he doesn't have a great eye for balance. Off topic, but I actually would have done efficiency modules as well but making the sprites was much more work than I thought it'd be and I didn't see a huge need when e3 modules already are so great.
I came up with the recipes by making a completely arbitrary equation loosely based on the vanilla module recipes; here's the snippet of code that reflects that:

        {"productivity-module-"..(tier-1), 4},
        {"advanced-circuit", 5 + 3 * (tier- 3)},
        {"processing-unit", 5 + math.floor(1.5 * (tier- 3)) }

So yeah it's kinda awkward. I probably should have stuck with the 5+5 setup.

Off-topic again, but here's a snippet from the code that determines how powerful each module was. I'm thinking of making productivity significantly more powerful if I am to keep the absurd costs. My friend argued that, despite the inordinate cost, it would still be unbalanced to give the allrounder any more powerful traits.
{productivity = {bonus = 0.06 + 0.02 * (tier-1)},
consumption = {bonus = 0.4 + 0.2 * (tier-1)},
pollution = {bonus = 0.05 + 0.025 * (tier-1)},}

Whoops! I have no clue how I did that. Ignore the second reply, lol.

A little stronger productivity would be fine I guess. Maybe something like 4/6/10/14/18/22 %, compared to the current 4/6/10/12/14/16% or so. Or maybe 25% for the highest level, which should make some ratios nicer. But don't increase it too much. Personally I see the ridiculus cost more as an end-game resource-sink (alternative to infinite research), and not too much as a way to get better machines (there are other mods with higher-tier crafting machines for that). These modules don't really have to be "worth it" to do that.

Also I like it to be infeasible to equip all machines with the highest tier. Makes it more interesting if I have to choose which parts of the factory gets them. Only my 2 cents of course ;)