Diesel Brothers were sued by a group of Utah physicians. Utah physicians for a Clean Environment, ( I believe). They were fined about $850k and required by the court to pay the legal fees for the Utah physicians, which was reported to be close to $1 million. How this is going to end, probably won't be good for Diesel brothers, or any shop doing this kind of work. I worked with a group of engineers, on DPF filters back around 2011 , and I was never, happy with the results. Caterpillar quit the over the road market, as we know, because they saw lots of problems, they didn't want to deal with. I don't recommend removing them, but they are a pain for many. Best be careful what one does, emissions wise. All that black smoke , just brings attention, the wrong kind.