Doesn't exactly matter does it.. if you do it smart you replace the ENTIRE exhaust system and you can then change it over in an hour at home..
Won't change anything, just goes to show our Government are c*cks. "illegal for road use" yeah do one pal
And considering diesels aren't tested for CO2 emissions I don't know how they can say this magically saves the plannet
The carbon and soot buildup has to go somewhere - Normally over the rolling hills on the m6, the total c02 output of the car is still the same.