I got one shipped today with my KM, but it doesn't fit my KM because it got a 'bobble' at the end of the stem
But it does fit my MTA QT, gonna try it later.
It lowers down the noise for sure, but I don't know if the smoke/taste is really better with diffuser. It depends on package method, heat management. Maybe with a diffuser you had a better packing/heat management than without it.