Does the Touareg, when equipped with bi-xenon lights, use the Xenon lights for high beams and low beams?

Yes. In Xenon-equipped Touaregs, the outer most lights in the Touareg's headlight assembly are high intensity discharge lamps, and are used for the low beam, the high beam, and as the daytime running lamps. In Touaregs that are not equipped with Xenon lamps, the out most lights in the headlight assembly are for low beam only.  more