Glenn,
Pipe is a DanMoto GP Extreme, (http://www.dan-moto.com) and the whole gig cost US$220 – exceptional value!
Interestingly, the Honda Fireblade ‘kit’ with mid pipe, clamps etc fitted up almost perfectly to the decrepit 4-1 that came with my wreck.
But it is all about the size of the header outlets, and if you contact them they will sort out what version fits best.