I concur that these kits would be beneficial. The Diesel Particulate Filter (DPF) works by trapping the diesel "soot" that would otherwise be expelled into the environment. The ECU will initiate a DPF cycle approx. every 2-5 tanks of fuel where it will run the engine super rich with the intent of super-heating the exhaust components and burning off the accumulated soot within the DPF. It takes as much as 1-2 gallons of fuel (exactly how much is wildly debated on the diesel forums) to "burn" the soot from the DPF. So, you are trading off soot in the environment for an artificially poor fuel economy. Also the DPF and cat are, by definition, constraints within the exhaust.
A typical DPF delete kit will allow you to replace the cat and DPF with straight pipe and the associated ECU program will tell the ECU to block engine codes when it cannot find its DPF, and it will also stop the DPF burn cycles.
The whole DPF debacle was an interim measure until the OEMs completed the development of Urea injection which is the preferred alternative for soot elimination. Urea injection will appear in all of the newer diesels from the OEMs and DPF's will be a thing of the past.
