I didn't wait at all to hear the glorious tones of a de restricted silencer. I had the dealer fit it ready for collection. I made a nicer looking bracket once I had a spare hour or two. The one I have is the hitchcocks Goldie pattern. Sounds lovely and rich. I had the end battle out as soon as I got home. The bike runs great with lots of low down torque. There is an issue with regards to the chrome, which is turning kind of "milky". Can't always see it. Depend how the light catches it. But I can say that I'm very happy in terms of noise quality and general running.
I'd talk to hitchcocks about what else they recommend with the euro 4, unless you just take a punt on whatever you fancy.
I've modified the rear end, rotating the rear guard forwards and making a smaller seat mounted rear light. Also a homemade mount for a single bar end mirror and a home made mount for a hip flask chain oiler.
Issues so far have been binning a duff chain after only 1000 miles, a leaking and failed battery after 3000 miles and a faulty ferrule where the evap tube joins onto the injector body. All rectified myself.