Funny you say about the irs in the commodores...
I actually weld a couple of brackets onto the irs rear x member for holdens at my work. (No not the one that broke ) You should see the welds on them that COME from holden. OMFG, they must have an apprentice down there, coz in a rack of 11 x-members, I pull out 1 from every rack which has holes blown, incomplete welds etc. I mark em and they get sent back to holdens.