If dvsa can get the ability to fully read all vehicles ECU ( wich is debatable) the I'm sure the remappers will find a way to show what is needed and hide the reality,dpf's a generally fairly reliable..may be an odd sensor or wash out now and again...it would appear Adblue systems are the unreliable and expensive bit...if this is brought into the MOT then a lot of older cars and commercials will end up valueless because of Adblue repair costs,and minimum wage earners in rural areas are going to be without cars