Are those pipes loud? Or they have something that dampen? They look like straight megaphones.. 
If you are looking for an exhaust system that is as quiet as a Gold Wing then these pipes are not for you. They are a bit loud, but not as loud as the Carpy 4 into 1 that I had preciously installed. There is a baffle in each pipe, which are available separately as spare parts from Webike Japan, Part No. MRS-H75-M02.
Eric
Good with baffles possible to tune the sound.
My Hindle 4-2-1 has a dark tone and possible to ride with less sound. It has a wide hole all the way,. Endpipe is perforated inside with thick layer of wool in its sides.
Another thing when twisting the throttle!
