Differences in GESI catalytic converters non-EPA and EPA versions

[bmw m3 s50]

Has anyone here had experience with GESI catalytic converters, specifically comparing the EPA-compliant and non-EPA versions?

From what I’ve seen, the EPA-compliant version is roughly three times more expensive than the non-EPA version. I’m assuming that higher cost is largely due to meeting EPA regulations and being approved for use in emissions-related state inspections maybe even slightly better material/coatings.

However, in my case, I’m not installing catalytic converters for emissions compliance or state inspection purposes. My primary and only goal is to reduce the strong exhaust odor that comes from running a catless system without sacrificing a ton of power or longevity.

I’m wondering if the non EPA version actually does the job at reducing the smell and would be good enough for me. I don't want to spend 3x more for the EPA version if the NON EPA version will do the job.

So here are my questions:

Does anyone have first-hand experience with the non-EPA GESI cats vs the EPA version?
Did the NON EPA version noticeably reduce the exhaust smell after installation?
Was the improvement minor or substantial?

Any insight or experience would be greatly appreciated!

[maupineda]

Is not clear what the differences are based on what they have published, but I think their latest EPA complaint cats have denser honeycombs plus the coating formulation. That will directly reflect on how much of the smell goes away. I think is worth the extra dough. Either EPA or Euro 4 is what you want.

[bmw m3 s50]

Is not clear what the differences are based on what they have published, but I think their latest EPA complaint cats have denser honeycombs plus the coating formulation. That will directly reflect on how much of the smell goes away. I think is worth the extra dough. Either EPA or Euro 4 is what you want.

Yeah, tell me about it. It seems pretty vague on the actual differences between the two. Just would kinda suck paying the extra dough for the EPA version, if the non-EPA version would work to get rid of the smell.