1. Im not sure that crack is in an area that will matter. Is it propagating to any sealed compartments? Is it just weight bearing?

2. can it be welded/repaired? Just because the shop doesnt do it doesnt mean it cant be done. Frankly if the tech had that happen on his personal car I'll be he would figure out a way to repair it.

3. Part is $2100 from Getbmwparts. Less elsewhere I'd bet... shop can come down. Or tow it elsewhere.

But for me Id find someone very good at welding