I can't say for sure and I haven't been a gear head for many years now so I'm very open to those with more experience. It appears to me that the headers (at least mine) didn't crack due to lack of support and weight on the flange but in inflexibility of connection and the movement of the engine. They sell some ball a socket flanges weld on's but it's unclear if that's really to allow flexibility (of movement) but possibly really only to allow flexability for arrangement. I know they make (or made) of flex exhaust but it was well unpleasent but I ran into this which looks real interesting. It looks like braided hose but it's for exhaust. Anybody ever seen this stuff???
www.mmohindia.com/automotive.htm