Ok, the pro's highly outweigh the cons when switching to HID. Well first of all the lighting output is far beter with HID, the bulbs last longer, and your lights can be sen from a mile away. The only con, is that in some cars the "bulb out" light wil come on. I think that it can be fixed with a resistor. The HID draws only 35 watts, while stock halogen draws 55 watts, tht is why the "bulb out" indicator will come on. My HID kit came out of a Porsche, but it is the same kit in many new cars (BMW, Audi, VW). My kit took a litlte "modding" to work in my 300E.
1987 mercedes 300E
1995 e320 conversion(hated the 300e grill)
Monochromatic Paint (Custom Blue)
Flat Badged (front)
custom "carbon fiber" console
18 inch HP EVO rims
Sold! Now I drive a Monte Carlo SS