stsainless does crack...just to let evryone know. cheap header...maybe, the fact that mines fully welded all the way to the "axle back" , what ever the reason may be it still cracked. AS FOR the install..as long as it bolts up the the cat ur fine. 4-1 is a pain in the ass to put in. 4-2-1 (2 peice) the gasket are bad for leaking. and they all have power gains in different rpm levels...