The reason I referred to the AIS was more to do with the soot you mentioned, rather than the dB killer issue. When the AIS is blocked there tends to be a little more sooting in the exhaust, partly because unburnt fuel in the system is not being burnt off, but mainly because the act of the "explosion" itself (the pop/bang) effectively blows out and cleans off excess soot from the internals, baffles etc. and, importantly with the stock exhaust, keeps the cat clean, free from soot and the damaging effects of unburnt fuel.

Just fitted my Exan exhaust yesterday and got a bit confused about how to mount it. Looking at the pictures in the first pages in this thread it looks like the exhaust hanger i mounted in front of the mounting point of the pannier frame. The only spot I could find to mount the exhaust hanger was the hole where i suppose the pannier frame should be mounted.

Do you guys know if this is the intended way to fit the exhaust?

The mounting point for the hanger supplied is off the rear pannier rail mounting point. The mounting on my bike on the early photos is different and off an under seat bracket to allow the tool tube fitting.