I honestly know nothing about HOW HID kits work and ballasts, etc. etc.
But I have been surfing the FitFreak.net forums about them and it would seem that there has been an uproarious good word about the "Xenith Xenon" when using them with Fits.
I would look into those if I were you - before buying a kit for the wife.
I plan to when I'm shopping for HIDs, but like I said - I'm still very novice in that category.
Check out this link if you're interested:
Gauging Interest for Xenith HID Kits... $140 shipped anywhere in the US!