I use Phillips Diamondvision for Hi Low and have AZNOptics LED's for parking.I too am interested in this upgrade. I have Philips crystal vision ultra in the headlights so I want to match those.
The size of the bulb is W 5W according to the book. I have yet to find a place that has halogen replacements that promise a Whittier hue ( I haven't looked hard though).
Keep us posted if you find something that you are happy with.