Did you have to remap or get a PC? Does it backfire when you let off the throttle?
I wonder if the Buell has the closed loop 02 system like my 07 Multistrada and other newer Ducs. If it does there would be a lamda probe sticking out of the exhaust pipe. Afermarket exhaust mods usually cause the engine to run richer so the cheap fix is connecting a device called the FatDuc manipulator to the wiring that comes off the lamda probe. Works fantastic and everybody likes them. Fools the ECU into thinking the bike is running leaner, don't have to buy an expensive ECU.