Yeh well i basically bought a 5w globe from my local automotive store. I first tried LED's but the beam they produce is only visible from straight on, which is suitable for cars that have sidelight refracting lenses but the C4 doesn't so i just used normal bulbs. cost me AU$10 but you should try and find good ones coz u get wot you pay for. Very easy to install too, just rotate the existing bulb out. The good thing about them is that all the interior lights (boot light, door sill light, footwell light) use the same bulbs. Anyway the last post i've had the car lowered 4cm (aparently a difficult job) and am customizing the door sill plates to put lights underneath. Should look good, i'll update when its done