I dont know if people are still reading this but i ride a 2008 xb12r and have had both the jardine rt-1 Carbon fiber pipe and now i have the drummer original.. first the jardine CF is the BEST looking pipe out there. my issue with it was the noise. the pipe was way to loud for me and the back fire on it was like a cannon going off on the whole d-cell. good news is the pipe did give me a little extra HP. atleast it felt like it.
the drummer is a nice looking pipe and even better it has a bold thumping sound. its still very loud but it has little to no back fire. i put the drummer on so i have no input as to power gain yet sorry.
overall im happy with the drummer because it has a better sound and i dont have to wear earplugs when im riding. if your just going for looks though then the jardine carbon fiber is for you.