Most halo kits like this are a single PCB in a round shape (hence the halo) and something to keep in mind with the 98-00 headlight is the shape of the inside of the lens. The halo has a good chance of obstructing your headlight's beam.
Alternatively, I'd suggest getting some LED strips (RGB of course) and sticking them along the bottom of the lens however you like. Doing it this way now means the LEDs won't obstruct the 9007's beam, however this introduces a new problem.
The normal LED strips in this configuration will now reflect off the lens itself, causing the light output of the strips themselves to possibly dazzle other drivers. While you could 'haze' the strips themselves in a multitude of ways, I'd seek out a different style of strip.
Normal LED strips are 'top' emitting, such as this strip here.
Your best bet is to use a 'side emitting' strip. Doing it this way still allows the strip to be stuck to the bottom of the housing, but the light emitted is now pushed directly out of the lens, not nearly as obnoxiously as with top emitting strips.
However, another thing to bear in mind is the heat, both when in direct sunlight or when the bulb is on. You need to make sure the strips are rated high enough for these conditions. Not only that, but the strips only use a double sided tape, which will quickly fail with this heat and begin to peel away. Some temperature resistant glue will be necessary.