The light pattern of the projectors in the headlights is decent; installing a set of HID's will throw a lot of light on the ground. I run a set of 6000K HID's in my low beam projectors and my fog light projectors.
I would like to note that I started out with a set of glass euro headlights, and later bought a set of 98 headlights b/c I grew tired of everyone giving me shit about having the "cheap" headlights. I installed a brand new set of euro's in my car, along with the 6000K HID's at the same time. A year later, I swapped in the 98's. The beam pattern on the euro headlights was significantly better than the 98's. The beam was more focused with a cut-off more pronounced on the euro headlights, and the light dispersion on the ground was a lot better. So much more so, that I'm considering buying another set of euros, and disassembling them to paint the inner housings argent like the 98's.
Long story short, yes, a good quality set of 6000K HID's will be a significant improvement over stock halogen bulbs.