You will not encounter any problems. The DPF & Catalisator is a filter which clean the exhaust gas before blowing it out into nature. Running the vehicle with 500ppm for long durations may only cause more soot, but usually the system cleans itself when driving constantly on the open road. Filling the tank with 50ppm every now and then will help to clean the filter.
Running the vehicle without the the DPF will only have an effect on nature.
Pajero `07 Did lwb
Jeep Gladiator `68 J2000
Kenwood TK-7100 VHF