Your right, the FR-S has the projector Halogen headlights! A HID conversion should be easy but it still don't look as clean as the stock HIDS. Plus the stock Hids are probably the bi-xenon auto leveling kind....
It won't be $2000 for the stock HIDs, more like $600 a headlight at most. That's what the 370Z HID lights cost from the dealer parts department.