I have 2 sets of RDL headers, 1 is a normal set about 2 years old and the other is a brand new set of Extreme Flow's. Both sets both seem to bow out on the ends. The pics are of the Extreme's and they only have 1 pull on them. Not sure if this is common or not so I thought I'd ask. I havn't had any problems with blowing the header gaskets but I have had some problems with cracking on the 2 year old set. Would cast ones stand up better and not warp? Should I get these machined and will they still fit fine with my up pipes after they're are machined. My heads seem perfectly straight.