You may not notice an increase in power, but you may find a decrease. Unlike crusiers the hayabusa's engine setup relies on the back-pressure created by cans. Buy a real set of pipes and map the bike, you will reduce the chance of a major engine problem in the future. See back-issues of Cycleworld's geek, a hayabusa owner wanted to take them off completely, the geek warned this would do damage to the engine. Gutting the cans may leave the same outcomes.