The current advanced mufflers are fairly similar to pollution scrubbers and thematically pretty weird, using air filters to filter pollutant gases.

I suggest changing them to Cataclytic Converters (CC), which would work as follows:

A CC has two inventory slots, one for input, and one for output.

The input slot would accept catalyst metal foils, which get consumed after set amount of pollution negated. After it has used a foil, it has a small chance to give a tiny pile of Platinum Group Sludge dust. (The catalyst getting dirty and turning into a mush)

The different tier CCs would accept increasingly better foils and give increasingly better pollution reduction with these foils. Some rough numbers:

The materials that are lower tier than the CC can be used, but do not provide any bonuses compared to using them in a appropriate-tier CC.

The converters shouldn't be too expensive to craft, but maybe have the tier specific Large Cell as a component, to represent the converter itself where the foils (catalyst mesh) is placed.

By having them automatable, this would allow a way to make your multiblocks produce less pollution, with a nontrivial automation task, as most multiblocks have the muffler with just a single side available (In base GT), and with these requiring air access, one would need moving inventory handling, for example with GT++ robots, frame machines or pistons.

Also to note:

1. Low tier turbine replacement for scrubbers so they can be used Pre-MV.
2. Automation upgrade for scrubbers so that they’re more usable.
3. For GTNH, May be beneficial to allow mufflers in more flexible positions within the multiblock. Would make automatic CC’s easier, but not a requirement.

For the low tier turbines I suggest two variants:
Bronze (Low Durability/High Efficiency)
Steel (High Durability/Low Efficiency)
So there's a bit of a choice between speed and consumption of turbines.

Scrubbers already have a low efficiency mode to make turbines last double their lifespan.

Can adjust the code slightly so they take less damage as a result.

Any suggestions on foil materials at all?