exhausted :) what system to install?

i thought it doesn't matter where the X is? Just for H designs important...
well, i want soft curves, no strong angles over 60 degree. That moves the X automatically into the middle between header and axle I guess.

My concern was for racing. Is an open headder better than trough the X? Or other way round does the X support the flow in high rpm's?
I mean a real X (4x almost 90° angles ) and not parallel pipes connected which just look like an X.. :)