I put an FMF (quiet version) on mine and I also had the shorty header pipe. Made a real difference in power but you need to jet richer and raise the needle but that's pretty straight forward.
I´ve got a Dominator silencer.
100% slip on. 5 min to replace.
Good price (160eur transportation Holland/Spain included)
2,7 KGr Vs 4,2 from the original.
dB killer included, a bit noisy for urban ride, in my opinion.
Supporting fitting on the pipe not included, so that the line is only supported by the cylinder bolts and the reare metalic belt.... too weak for the country, in my opinion.
The engine breaths much better, with faster rev raise.
Not ridden yet, will tell about power increase after first ride... but it seems performance will grow.
The metal strip to hold the silencer is a bit weak (too thin) AND is centered over the silencer. When fitting it, half silencer becomes over the wheel, under the mudguard so, when compressing the shock, the wheel touches the silencer.
Another modification to be made !
Gone for a short ride; Don´t realize an strong power increase, BUT a faster response and revs raise is clearly noticeable. Appreciated at the country !