I am still a little unclear on the effect of cutting the grey wire. After running the bike in on the road I noticed an immediate increase in top speed of about 10mph, but this was combined with cutting the throttle stop. From the various threads cutting the grey wire moves the ignition timing from WR to YZ characteristics. But if the Euro models do not have this, then why do they have it for the US. I would assume the grey wire restricts the bike along with the throttle stop to pass the US emissions tests? I would assume this restriction is not due to noise levels, as the UK is just as sensitive on noise by my understanding. Would the grey wire in place help with slower 'Euro forest riding' where you are lucky to hit 30mph and not a tree!? Does this only affect the higher revs?