Hi, no in the end I got him to put a 3" pipe down to the twin pipesWe dont have a law in NZ at the moment regarding the cat,but it is coming. It seems to be a lot more responsive all over the range. I really couldn't believe the difference it made, that's why I thought my valve springs might have been an issue. <{POST_SNAPBACK}> I replaced the cat with a 3" pipe (for a temporary trial period) and it resulted in a similar gain on the dyno to yours. As you have reported what was more impressive was the increased throttle response across the entire rev range. My valve springs also need replacing however this only restricts performance above 5000rpm so I think you can thank the lost cat for the bulk of your useable gains. If noise is an issue replace your centre muffler, I have a 3" system with centre muffler intact and the cat removal made very little if any difference to the sound, until you put your boot into it that is. Congrats on the great results <{POST_SNAPBACK}> Thanks Jordak a great reply.I was hoping someone would come up with a similar result. I thought it might have been all in the mind.