No codes, No check engine light. The computer has been properly tuned. in fact to run the tune that I have and the boost settings I have, according to the manufactor (Revo), I have to have the "Cat eliminator downpipe" I dont know why i'm not the mechanic just the driver.
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Acording to the guys that built the car, who seem to really know what they are talking about, there is a difference ON THIS CAR between having them and not. I've seen American muscle where I agree 100% a good set of flow through cats are highly effective.
1.8t is completely different engine. not even the same block.

See in that image where it says "Test Pipe"? That means it is only allowed to be installed for testing purposes ONLY. In other words if a tech suspects the cat as being a problem they can install that test pipe and drive it temporarily to see if the problem has been corrected. There are special provisions in the EPA regulations for a licensed tech to operate a vehicle with a test pipe installed in lieu of a converter for diagnostic purposes only. That is why it SPECIFICALLY says "test pipe".
I don't really care what you do it's just important that you understand the just because other people are doing it and just because there are no inspections doesn't make it any more legal. There is a saying, "Just because you can doesn't necessarily mean that you should" that people have forgotten about of the last several years. I get ticked off every time I see someone fly past me doing about 70mph in a 40mph zone. I get ticked off every time I see someone run a red light or illegally pass me on the wrong side of the road. This type of behavior seems to be getting more and more popular because cops simply don't give a hoot about it anymore. They are too busy relying on other companies to operate red light cameras or radar cameras to care about enforcing the other rules of the road. But does this mean that the other cars are allowed to do that? NOPE.
I was visiting Florida a few months ago with my G/F (who is from there) and we met up with an old friend of hers. This woman was 30 years old and drove her Mazda 3 about 80-90MPH everywhere she went - swerving in and out of traffic the whole time.. on SIDE STREETS. If that's not bad enough she did it while smoking a joint and keeping a large bag of weed in her center console. After about 30 minutes of this nonsense I made her turn around and take me to my hotel. She turned it into a whole "you're too much of a wuss to smoke weed" thing but I was looking at it as 1>I don't want to spend the night in jail and 2>I don't want to get killed when she wrecks the car. After a huge fight with me threatening to call the cops on my cell she finally agreed to take me back. Luckily my G/F understood and I was really just saying the same things she didn't want to bring up.
She went on to explain to me that down there the cops don't care and if they catch you with marijuana they make you dump it out and give you a warning. I told her that things are handled a little bit different where I'm from and you don't get caught driving like that AND carrying enough weed for it to be a federal offense without at least spending the night in jail. It must be something in the air down there I swear!
I should not that two weeks after we came back home she totaled her car and cited for having illegal substances. Unfortunately her daddy is a wealthy businessman and reprimanded her by once again buying her out of her problems along with a brand new car. She'll never learn.
Anyway.. my point is that you might think you're all cool and stuff for "getting around the law" but these things do have a way of catching up to you. With a car set up for performance like that you're going to tend to drive a bit more on the aggressive side.. and one day you're going to get that one cop having a bad day and you can probably guess at the rest.