i just boght a nd installed the dc 4-1 stainless on my si and it looks great and its made of better material than ceramic . and won't crack like ceramic does over time. it will turn gold ig you clean it before you drive your car and heat it up the rainbow effect is from oils and other things that get burned on it. import horizon is a good place to find it they also have the jdm one too for 365 shipped.