Lewis, when you remove the stock downpipe with the catalytic and install the race pipe[nocat] you will have some changes with the car. You might have exhaust fumes you never noticed before. You will see a ton of moisture on cool mornings steaming your rear window on occasion. You might see black smoke under hard acceleration in your mirror. Those are all ok. But if you have all kinds of blue smoke, you have a bad turbo exposed but I would be surprised you did not smell the oil in the exhaust before. I have Cork full and no smoke at about 8000 on exhaust. good luck