brightness is 35watts, color temp on most OEM is 4300 because it gives the most visible light. As you go higher you get bluer then purpler light which can look cool, but won't give the best performance. (less visible light, and more reflection back at you in the rain and snow) 6000 is a nice compromise as most people said.

personally I'd just get a set of bulbs for $10-20 from ebay and call it a day.

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2006 Audi A3 2.0t DSG apr stage 2
2002 BMW X5 4.4
1997 BMW 328ic sport. moreagrun metallic
1989 BMW 325is with / M50b25nv swap