My experience of Janspeed is that the fit is nowhere near as good as it should be (I could never get the Janspeed on my old Cinq. to fit properly) and, although the main system may be stainless (not sure in this case?) - the tail pipes will rot and drop off within a couple of years.
That's why I'm going custom built this time - you get to chose your noise level and tail trim, as well as getting a guaranteed fit.
Janspeed are not the Janspeed made famous by racing success - they're just another accessories manufacturer / reseller these days - the original Janspeed went bust in 2001.
The system I had was from the original Janspeed company.... I'm not surprised they went under!