Modules are overhauled to be available at red science.

The first 3 colored modules, red yellow and blue, can provide a very small boost on what you want to machines. However, they also have downside effects (like consuming more electricity) so they aren't that useful.

The second tier removes the negative effects,, but their effects are small and aren't that powerful.
The third tier provides more powerful modules.

All of the tiers have a different recipe chain from vanilla. If you want productivity modules, you need to produce speed, and to produce speed you need to produce energy modules.

The white modules are "good for everything" that are a flat upgrade to all machines. But their effects are weak, so you'll want to upgrade to color modules eventually. If you have the quality flag enabled, black modules appear in all techs. Those are pure quality modules that aren't that different from vanilla (+1%, +2%, +3% quality) and are made with the color modules.

Vanilla modules are kept for science & item production, so I wouldn't change the vanilla balance for science packs. By default they don't give bonuses anymore so you use the rainbow modules but you can enable them in the startup settings. Module graphics borrowed from Mr.SmoothieHuman