Congrats on the car.
Regarding lighting color on factory HID, this may be a slippery slope. If you change the color of the low beams to something cooler (toward white/blue and eventually purple), you might find that the LED accent lighting starts looking relatively warm (toward yellow). It seems there are aftermarket options for the LED "underbrow" lighting in the low beam projector, but the ones in the bumper would probably involve some custom work. Each time you adjust the color of one (low beam, underbrow, bumper LED) the warmest one can look yellowish, even if it was the right color of white before you started.
For reference, see this picture, which has a 5000k HID bulb on the passenger side and factory halogen on the right. Notice how the bumper lighting looks white/blue next to the halogen but starts looking white/yellowish next to the HID? This is what can happen if you replace your low beam bulbs with something cooler in color.
If you still want to give this a shot, you won't need an HID kit, as these are designed to replace cars with factory halogen lights. I believe you can replace the bulbs. According to Sylvania's bulb finder:
link the gen 6 Camaro uses D3S bulbs. The factory bulbs are probably 4300-4500K. If you want something more pure white, 5000K is probably the sweet spot, with 6000k going toward blue.
Word of warning: if changing bulbs on an HID equipped car is anything like a halogen (non-RS) equipped car, it is
not easy. Very little space to fit your hands and difficult to get leverage or even see what you're doing because of the tight space, odd angles, and shape of the car. It can be nerve wracking because the bulbs are fragile and expensive. It may be safer (maybe even easier) to remove trim parts or even the headlight themselves for access, if you're willing to go that far. One important consideration would be whether the housings have sufficient clearance for aftermarket bulbs--I've no experience there, so perhaps someone who has tried this can chime in.
Hopefully tribal knowledge will eventually get us to the point that this is a routine thing with a clear cut solution. For now, based on my related experience anyhow, I would rate this mod (replacing factory HID bulbs) as something for the adventurous and very determined. As you've noticed, GM did a great job with the overall lighting setup on the RS. Best case, you get the color you want and a few scraped knuckles. A little bad luck, and you have to scrap the project because something didn't work, and you're out the cost of the bulbs. Worst case, something bad happens that isn't covered under warranty. In any case, the system won't put more lumens on the ground than the factory setup, as that white/yellow lighting is optimized for performance and the projector was engineered to work with the factory bulb.