I'm just curious if there's a reason you didn't do a lower 'X' or 'V' (though less twist resistant than X) brace?
Was it to save a little bit of room between the strut towers?
The 'x' would resist twisting in the same manor as this. This just makes two 'H' shapes between the C and D pillar which does nothing but put the aluminum section into torsion/twist short of adding another bar to help limit the towers flexing towards one another. Likewise you'd have the same with the X (the torsion/twist) but now it anchors between the strut towers with a broader 'x' and fewer parts.
Just spitting the first thing I noticed.
Still like the work