they're insubstantiated chap...you can't be affected by internet rumours of people that have probably no idea about manifold design or any physical experience with them. Yeah, i've had it on for a while now...I wish I could give a more accurate description of it's effectiveness, but my car is less than healthy. Regardless, at first I ran it without the Blitz decat being braced...and that was for at least a month...no issue. Braced it up now, but it always pulled very hard, and unlike the CT9 the response would be relatively good after 5000rpm...i.e. the boost didn't really tail off...