My 01 GSXR 1000 has a stock bolt to flange muffler. Many aftermarket slip-ons are not flange friendly. They are slip-on with a mid-pipe and clamp. Has anyone cut the stock flange off to accommodate a slip-on? Please share tips, thoughts, experiences, pics and anything else relevant. Thank you. Regarding tuning, I have been told two things. (1) Slip-on should not require tuning. (2) After installing slip-on, should have it tuned. Any advice? Thank you.