Agree with your sentiments. I am also trying to reduce front weight; that bar saves a little bit but then I am installing an oversized intercooler and... sigh.
There is also a thread on the subframe 'brace' that the M3 uses. Talks about rigidity and how to fit it to the triangle bar setup our cars have: https://www.e90post.com/forums/showthread.php?p=26613054#post26613054
[EDIT] I keep forgetting that 1series !== 3series in all regards, so hopefully this stuff is applicable...
The m3 subframe is different and uses a belly pad for rigidity and is way stronger than the flat bar in every direction.
The belly pan is made from very thick alloy plate and you can feel the stiffness it adds to the front end through the corners.
One has to experience the difference between the n54 and s65 to appreciate how much better the v8 is in this chassis.
I'm not knocking the n54 at all, i love the power and ferocious delivery it makes but its more suited to a drag setup than a canyon carver when compared B2B.
With the n54 i was struggling to hit 1g and being on the limit through the corners, now I'm easily pulling 1.1g's with the s65 and street setup.
Totally different but both frames will bolt up to the chassis with no modification.