I bought a www.xenondepot.com kit for my 2000 sierra (it also has stock denali projector headlights previously installed). No one could tell me whether or not the lights would have the correct cut off or not because they are not designed for HID's. I put them in and they have a perfect cut off. I would buy the kit and see for yourself.

A cheaper option is to replace the stock h13 bulbs with h9 bulbs. Minor modifications to the base of the h9 and there is a difference in light output (not HID quality)

a picture of my lights cutoff (click the picture for a full size version)