[johnsjmc]

I am a class A tech in Ontario also and I think it looks more and more like a failed catalyst. The catalyst essentially works in 2 sections.The front section of the cat "strips"the oxygen from the NOx molecule and adds it to the CO andHC in the rear section to change CO to CO2 and changes the HC to H2O. When all 3 gases are high I suspect a catalyst failure. Your high Nox means less O2 to use in the rear to lower the others.There are aftermarket high flow cats that can be installed in the exhaust in place of the factory style. Any good muffler shop can probably do it for about $250 Cdn ( often plus premium if its a porsche but shouldn,t really be any harder)