SS headers are not worth the time, money, and effort IMO. they are almost purely a cosmetic mod. they suck when it comes to performance. this is why. they dissipate heat into your engine bay which does two things: heats up your engine bay(duh, which may have more adverse consequences on performance) and the dissipated heat causes your exhast gas velocity to slow which causes more backpressure, inefficiency, and loss of hp. the ceramic headers keep the heat contained so that your engine bay doesn't heat up and your exhaust velocity doesn't decrease, leading to better overall engine performance. i personally have never heard of the DC ceramic header cracking. the ceramic headers that crack are usually the cheapie ones you buy off ebay and such.

to answer your last question accordcoup94, yes the headers are steel they just have a ceramic coating to keep the heat from diffusing into the engine bay.