in terms of hp, acceleration, and top speed. thanks

 

Dirt wheels had a pipe shoot out for the z400 a while ago. The pipe that made the most power there was the CT Sonic pipe followed by the HMF. But not all the pipes were included in the shotout. Some were missing like the sparks pipe and various other. I hope some one else can help you by posting exact numbers.

 

The HMF was not second. Read the test again, and you will see the Pro Circuit pipe tied with the CT Sonic for best pipe. Have one on mine and love it. It's quiet too.