Just to add a bit to this thread.
I've heard lots of chat about the cat and leaded fuel over the years.
All I know is i've ridden my previous 1100 with cat across the world and although in countries such as Pakistan and India it was plinking a lot it never caused a problem. When I brought it back it flew through an MOT. My current 1150 has been round parts of Africa, Russia and Ukraine where the fuel is poor, again no problems with the cat. I have only recently in the past few weeks fitted a y piece. Don't really know why I did this as the weight is so low you don't feel it. Still, its done and i'll see if I feel the difference on the next ride.
Hope this helps.
