The technology used in the HIR bulb is called Halogen Infrared Reflecting and is relatively new.

Rather than having a tubular shape, the HIR bulb has a unique spherical shape, centered around the filament.  And, as the flash in this photo shows, there is a faint iridescent coating applied to the inside of the bulb glass.  This microns-thin film is the key to the bulb's light output.  The film reflects a portion of the infrared light back at the filament, causing it (the filament, not the glass housing) to become hotter and, therefore, burn brighter without shortening the bulb's life.

The result, then, is a brighter light without shorter life or incompatibility with stock wiring. The beam pattern of your headlights will not change, but there will be considerably more light within the pattern.   You can read about HIR at the website www.bmwz.org/articles/lighting/0506trick/