Only one way will clear the factory rear mount which is already a close shave near the hoop in the bar. I suppose it also barely installs one way (the correct way) with everything around it already installed in the car. That is the best advice I can give as I installed an Elantra bar with everything else installed around it, and my turbo setup just needed bushings when it got fiddled with.
The FSM only give a few clues as to orientation at the end points, Click ME
Here is partsouq's diagram ASA interpretation:
I think I have it, the hoop that clears the rear mount, should be pointing up like a mountain in a landscape scenery scenario. This leaves the outer ends of the sway bar, angled slightly upwards, versus downwards compared to a flat plane with the ground.