First of all, great exhaust. I only removed it to try and locate the source of a low power issue I'm having, not to bin it.
Having just removed it I have discovered an issue. This box, arrowed, contains a square nut. It means you only have to use one socket or spanner to bolt it on as the box stops the square nut rotating.
When it's nice and clean and new that is...
My exhaust has been on for about 18 months. It is still solid but covered in surface rust and crud etc. When I tried to remove it, the nut inside the box simply turned with the bolt and split the box apart. Then it just rotated freely. Obviously I couldn't get a spanner onto the nut and had to improvise. After about an hour and trying with thick bladed screwdrivers I finally managed to wedge a narrow chisel between the box (there's not a lot of room and it was further disintegrating with each attempt) and the nut and with copious amounts of WD40 it finally freed.
The box was getting really chewed up to this point and I was starting to wonder how the hell I was going to get the exhaust off.
Once finally removed I hacksawed the remainder of the chewed box off and put the exhaust back on using a socket on the bolt and a 17mm spanner on the square nut.
If you buy a SIP Road II (and I recommend it) I would remove this box before fitting and just use a spanner. It could save an awful lot of grief later on.