My Chaser has factory HID, I know all about them.
They're adustable... And the parabolic dish, housing and reflecting lens on the headlight are designed specifically for the light pattern a HID 'bulb' emits.
An AE82, KE, or whatever, does not have these things. The resulting effect is akin to shining a spotlight into a saucepan. Fine when everything is dead level, but as soon as you go over the tiniest bump you'll start flashing people. This is why they are illegal.