QUILL RACE CAN
(The following pictures don't do it justice)
The only performance modification that has been done is the fitting of a race end can. After much reading / research, I decided that a full system was no good, because I wanted to be able to convert back to standard quickly whenever I wanted. Also, some of the motorbike press had fitted race systems, and although they gave up to 10-12bhp more, they affected rideability through the throttle response below 5000rpm. (The small headers are the reason for the good low down grunt. They also slightly restrict top power. You can't have both - well, Yamaha do through their EXUP valve.)
That only really left an end can.
Since the flange on the end of the headers/system is round, it had to be a round can. I have seen some oval cans on these bikes (also ZX6R / ZX7R) and didn't think it looked too neat.
I finally opted for an Anodised Titanium can from Quill. I bought it from and got it fitted (you could do it yourself, but I wanted the dyno runs) by a company in Essex - Dyno Speed Developments.
These are my findings
Anodised Titanium is beatifull
It is also fragile and has marked up all ready (the wind buffeting the cover was enough to mark it).
It is quite loud.
Gives good power increase straight from the box
Jetting - you should really get it done.