Hi
i have fitted the staintune pipes to my duke,they are good quality and fit well.
The weight i estimate to be 5-6kg for the pair.As for performance they have givern significantly more torque down low and a good surge of power up top.At present i have not fitted the akra mapping as the dealership would not do it, as i did not have the akra pipes(on ktm's advice).All i did was allow it to idle for 20 mins, it still feels a little lean off idle, but is generally fairly good.