Hey Chuck,
WHat's the airplane?? Articulated headers work great and save you lots of headaches in custom installations. As far as headers failing due to soft mount systems - I've never had it happen (broken a few in some ugly, vertical landings [

]). I have an MK Super VR-90 with a Hanno Special in it. The header had more than 500 flights on it before I installed it in the VR-90 which now has 920 flights and counting. Back in the days of hard mounted engines and pipes I did have some headers fracture at the tube - faceplate junction.
Happy flying,
Will