I run a D&D Fatcat with the big bore wrapped baffle on my stage II 103. Even with the wrapped baffle my bike is "noticable" especially when on the throttle but the results are awesome. As noted in my sig line, my little stage II 103 with SE 255 cams and no head work makes 92 HP and 106 TQ at the tire.
My Fatcat with the big bore baffle pushes me to 112/121. Love it.