I think it depends on where you are located...here in SoCal, we almost never need the fogs, so running an HID kit isn't necessarily impractical.
On the other hand, it makes you an easy target for a cop that you might be running up to in the dark. HID fogs and headlights = street racer (at least that's my opinion when I see those 4 bright lights).
E90 M3: Some cool stuff...more to come
Ducati S2R 1K: Bucket full of mods