Is it an asymetric system that you have fitted (looks like the standard one , short u shaped pipe from rear cylinder) or a 50mm full system ? (completely differnt routing for the pipe from the rear cylinder)
Full systems are available in 3 sizes , 50mm , 54mm and 57mm dia , the 50mm one is NOT reccomended for the S , only for the standard 999 , if a dealer has sold you a 50mmsystem for an S take it back
