I've been using the Bosch H4s on various 911s. Relays are highly recommended, the bulbs last much longer, saves the hi/low switch from dying, and protects the wiring from burning out and starting fires. I use the 130/100 watt Narva bulbs from Daniel Stern. Very high quality German bulbs. BRIGHT!!! The ones in my White car have been going strong for a year and a half (low beams always on as daytime running lights).