Ibiza: Diesel or gasoline?

Hi, I’m playing with the idea of buying me an Ibiza as a new car. I’d like the 1.9 TDI at 74 kW. Unfortunately, there are no particulate filters yet. How do you estimate the cost of retrofitting, if this is soon required by law? – Is the higher price for the diesel compared to the petrol? Greetings, Carsten