So i had a GSXR 2013 and decided to put 09 header on. So when i got the new gsxs1000 I looked around for headers and exhaust. Roughly 1000 bucks and not what I was looking for so I cut the stock exhaust. Saved the cat and set valve function. I added the 09 set up because they have tons of choices. So for $230 I have a good set up. PS. The 09 header fits but oil change would be way to difficult. Thats why I cut the stock header.
3 inch to 2.25 exhaust adapter. Then any 09 gsxr1000 slip on. Yes, you do need to remove header. Cut just before the exhaust can weld. Only around outside if saving cat. Cat is roughly an 1/8th inch under the outside can. Be careful cutting if saving cat.