Need help for the interior light bulb size!

[cooleric2000]

I am thinking about having all my car interior map lights, dome lights, step courtesy lights changed to White LEDs.
I have checked the Osram Guide but still a little bit confused about the bulb sizes I need. Can someone who has did this help me out, thanks a bunch!

[grimreaper]

The overhead lights are 'Festoon' (578) type, approx 40mm long, 10mm diameter, and I would say about 10W rated.
The footwell lights are capless (906) type, approx 10W rated as well.
I have just changed my overhead lights out for some of these (DealExtreme: $6.01 Car Festoon 2W T10 100-Lumen White 6-LED Vehicle Light Bulb - Stainless Steel (DC 12V)) which are very white, quite bright led replacements,they are however a little short and I had to use some ali tube to sleeve the end connectors to extend them a little.
As for the footwell lights, I changed them to 921 type indicator bulbs (21W rated)