Header question

[86_6series]

86 635CSi_US.
Custom exhaust guy is having trouble attaching to the top 2 inch collector box
which is very close to the firewall. They're Ireland headers on a Hartge B35 head
on a B34 block. Has anyone ever had similar experience or problems customizing
exhaust pipes for these headers with close interference at the bottom curve of the firewall?

Any and all input is encouraged.

thanks
bob V

I'll post on Bimmerforums also