Thank you Andrew for the research.
My take on the suspension member stay, is that it is transferring loads from the vehicle body to subframe. Then again, it could be doing the opposite as well.
Seeing that the subrame is much stiffer, I can only guess it is to prevent body flex and to transfer load to subframe.
The SF 6 point brace, takes it one step further, by extending that load transfer further aft and keeping a continuous, 1 piece member without any breaks or gaps. Resulting in a much stiffer set up.
Why did Nissan put it in? I agree that it was a cheaper, and easier set up at the assembly line (and for future maintenance). Otherwise, I think they would have to extend the subframe.
Why didn't Nissan just leave it out? If there is minimal torsion, flex, body roll, whatever you wan to call it. From my understanding, Nissan is building these cars for the street, not the track. So the objective is driver and passenger comfort first, track and sport secondary.
So, I think Nissan felt that there was some sort of uncomfortable feeling/ride or perhaps, a long term detrimental affect to body and frame.
I'll buy point number 1, as Nissan's cheaper alternative to a full subframe. Not point 2, as not needed.
I'm not an engineer, just what I observe.
