mancini tube upper control arm failure....

Still wouldn't break the weld. The other thing is if I remember correctly the car is from Detroit. The arms were bought in dec of 08. They broke in may of 09. How much use have they really gotten in that short period of time? I know that in jersery the weather didn't allow all that much use. And I believe that Detroit has a little longer and colder winter.

The assumption implied is that the A-arm broke during regular street driving causing the accident to jump a curb and hit a pole.

Maybe it broke after the curb and pole impacts. No proof otherwise. Curbs and poles are not something you drive over in spirited or racetrack driving.

Ok, it shouldn't break the weld like that. But it shouldn't hit a pole or jump a curb and speed like that either.