Is anyone using these? What kind of power gains did you get from it..I didnt see much info on them and was looking for an install guide to see what they are like to install.
http://www.steeda.com/products/charg...gs-mustang.php

Also how come they are only $59 at steeda but Brenspeed and AM are selling them for $100 that seems a bit off.

 

They just plug the holes where you have removed the butterflies and shaft. Most guys see a little performance gain at high RPM. You may however lose some torque at lower rpms.