I replaced the stock bulbs in my 1999 M Roadster with Philips Bluevision and Allweather bulbs. The entire process took about 15 minutes.

The part numbers are:

Philips 9006 55W Bluevision (low beam) $34.95 per pair

Philips 9005 65W Allweather (high beam) $34.95 per pair

I recommended the Allweather for the high beams for mixed weather driving.