So first of all I just got a Magnaflow catback last week. Thanks to all the posts with soundclips and performance opinions. So far I am very happy with it. It is a little louder than I expected but it is a nice deep sound, and while it won't be mistaken for a V8 I am still impressed.
However on to the subject of the post. I just had my first fill up and was a little surprised by what I found. Pre Magnaflow I would be good for approx 550km per tank, post Magnaflow that seems to have gone up to approx 650km. Sounds like I am bullsh!ting? Well it didn't take much to figure it out. I went 340km on 41L = 12L/100km @ 80L tank / 12L/100km *100 = 666km or 416 Miles per tank.
Does anyone else have any experience with this particular setup and fuel economy/tank range experience? Almost seems a little too good to be true.