i dont think there is enough back pressure with the D&D's. ever since i put mine on my bike has been idling rough and hickups at 12 to 1500 rpm. if anyone has any other ideas than this please help me. this problem only started ater installing the D&D exhaust. now the bike is running lean. i wish i would have bought the hauk perfomance mod. i had one on my 06 xb and it was awasome.