Yeah, one of the first things I did on my previous diesel car besides removing the catalythic converter (which was all clogged up by soot anyway). This resulted in a 5% lower fuel use as well but also a lot of extra NOx and CH output. Not very good for the environment. Nowadays you shouldn't be buying a diesel car.
Be aware that GPF (gasoline particulate filter) and EGR is coming to petrol engines too (not sure about petrol hybrids).
For instance, the VW up! GTI is fitted with a GPF, to meet emissions limits. I don't know if the filters are any better than the old DPF's which clog all the time if used for shorter journeys. A friend of mine had a rather interesting experience with a Suzuki diesel (Ignis, I think) which ran after it was parked. Apparently, a barely-documented feature where if it detects risk of clogging, it will run the engine despite ignition being off for about 15 minutes at reasonably high rpm to purge/regenerate the filter. You can stop it by turning the car on and then off again, but could be, err, "interesting" for people who park in garages who don't know about these features.
It's been about three years since they have been introduced (Euro 6D)
They won't clog as DPF do because the temperature is inherently higher in gasoline engines (clogging effectively begins on a longer full throttle acceleration, regeneration begins the moment you release the throttle and a couple of seconds later is done. Or so say all the data travelling on the bus)
Customers have already lamented about the GPF as the performance/rs/gr version of the car sounds effectively like a diesel (weak sound, changing the exhaust does nothing if you don't bypass the filters) and of course performance curves are worse if you compare the same car before/after they fitted the filter.
Too bad these don't do anything for particulate emission, as with euro 5 already the particulate emissions from the engine was lower than the particulate from wheels and brakes. It seems that Euro 7 will FINALLY introduce a limit on those, it was about time. It depends on where you leve but here (pianura padana) the weather, the alps blocking the perturbations from the north, the high humidity factors, we live inside a permanent fog, whenever it rains the day after i have regained 2/20 of vision, the air is so clear. And cars are not entirely to blame, certainly not diesel engines.
Which, by the way, i intend to keep using and buying. Going gasoline simply doesn't make sense for me and most people around here, real fuel consumption is still too high, hibrids that would offset the fuel cost by going on battery during work-home commute have too high initial cost to consider unless you don't need it, there is basically no public transport unless you go to bigger cities. I am trying to find a new house so i can switch to riding a bike to work most days (which i try already to do during summer) and keep the gas guzzler for the nights out and weekends and holidays, but real estate is currently a disaster. half your paycheck to pay for a single room apartment, in small towns, like it was the centre of Milan.
And next car is probably going to be a Van. My octavia is already a microcamper
Anyway, our permanent fog is composed mostly of PM10 from heating, industry/electricity, burning of wood residue from trimming and only then cars. PM10 in cars is ridiculously low already, yet they are blamed, blame the person who can't do better instead of providing the alternative (bike lane on ALL main roads between cities and towns would be a good start, more effective public transport would be nice too. It would take me 1h30 and three bus changes to go to work instead of 15-20m by car or 30-35 by bike. Bus are used almost exclusively by students going to school and coming home)
But it's wood burning is what really gets me, it's the most stupid thing anyone could do in this day and age. Not talking about burning wood for home heating (sill.. Though we do have a stove, but it's a new one, it meets the newest emission standards, and we will start using our own wood that we planted for the purpose so the cycle should become self sustained) but burning residue while instead you could chop it and use it as a fertilizer, or compost leaves, that is just insane, but it's impossible to change people's mind. You get dead birds in your lawn as a warning if you don't mind your own business. Freaking old people with their old ways. And not many years ago wood residue burning would emit more particulate than cars over a year. Cars have only become better at it