Catless downpipe on the other end stinks and is considered tax fraud in switzerland.. car stinks / test says too loud, you drive behind the police to the next garage, up on the lift, catless downpipe found, huge turbo found, car gets impounded, you‘ll be registered as a bad boy and fined about 5000 francs.. i‘d rather not risk the police finding everything illegal on my car because of a downpipe
I did not even consider the hydrocarbon, NOx, etc. stench result of a catcon-less downpipe as the reason for suspicion in the first place.