Long story made short, had to buy a $410 new exhaust manifold due to breakage at the flex joint. Unusual problem but not unique, I have seen a similarly damaged manifold for sale on ebay real cheap. Cause of failure most probably damaged engine mounts. KlausC gave good tip to check them: "Leave the car in Park and gently rock the car back and forth. Watch the top mount and the forward mount under the radiator for flex and compression". I am not seeing a break or damage anywhere. Any experience noted with these mounts just compressing to uselessness? They look "about normal" though I've no measurement of the height of a new unloaded mount.