I just walked out to look at my bike. I have the tall engine guards from Hitchcocks. I don't have the TEC 2-1 exhaust.
Stating the obvious, I would modify the guard and leave the exhaust header alone.
Pretty simple really. I would remove the section of the guard's horizontal cross bar that is in conflict with the header.
Replace that section with a split "surround" piece. Obviously, it gets welded in.
Here is the good news, that surround piece is a readily available big end of a connecting rod from a 350 Chevy V8.
Cut to fit.
I think you can see the path. snip, snip - buzz, buzz. I have several that were given to me by a local hot rod shop. The big end will fit around the header and installation is "bolt simple". If a SF Bay Area member wants to pick one up PM me.