tph1,

I checked the numbers for the pipe set up I have on my YS 110. It has a Hatori #674 with the cooling header # 580. The system works well for me. If you have a pipe tunnel, I would suggest using it. I love how quiet it is and personally I can't stand the look of a muffler hanging out of the front of a nice looking pattern ship. But getting back to your original issue, it won't increase your power.