I want to buy this 2nd hand Scorpion Titanium slip on exhaust. The seller said it is for 01-05 GSXR models. He cannot confirm if it is for the 600, 750 or 1000. It has a four screw bolt. My question is if the back pressure for a slip-on exhaust different for a 600, 750, and 1000? Will this impact the overall performance if I installed a slip-on that fits a 600 but is suited for a 1000? I have an 01 GSXR 600 and Im not sure if it is a good idea to buy this in case if it was meant for a 1000. The seller said there is no indications of a model# or serial# on the exhaust.