Originally Posted by snrusnak
it is really not worth it, they are very helpful and like said hardly effect performance nowadays, and without them you also get a terrible rotten egg smell.
I don't know about a rotten egg smell with the new diesels, that would be hydrogen sulphide, H2S, and when H2S is burned it forms sulphur dioxide. It's less of an issue now with the ultra low sulphur diesel. The palladium in the cat does split the SO2 molecule and there's minor recombination with the water molecules to reform H2S, but it's minimal.