The quiet core insert can be used with NS-4 style DR.D exhausts. The insert can be installed and removed very quickly. And as the name suggests it helps to reduce the sound level. Although you will experience a mellowing of the power by installing the insert there is not a significant power loss.
* This product works with the NS-4 systems ONLY.
** Images are for reference only, they are not model specific. Actual quiet core insert vary slightly from image provided depending on model.