yes, everythings are custom made, i've seen quite a few of LHD s15 in Taiwan already, because registering a RHD car is impossible in Taiwan, thats why they had to convert them to LHD in order to register the car and they use some other nissan chassis no. because GF-S15 doesnt exist.
Changing from RHD to LHD isn't really worth the hassle unless required by law.
Alot of people are scared to sit on the wrong side of the car (in relation to which lane they drive in).
But most people who try it, only finds it awkward the first 15-20min.
My lights have been converted too. But the light pattern of stock S15s are pretty flat, so I don't think you'll have any problems with blinding people.
Yea some people ship over Skyline and S15 to the US through some shops like Motorex, to legalize them (emission, bumper law and etc.) However, it will get quite expensive (some almost double the price of the original car), therefore....what my friend did (also a silvia lover), is just to get a S14, swap the SR20DET engine (not available on silvias there), then change to the S15 front bumper and lights. But for skylines, they need to legalize them.