Okay, so I've been a bit OCD about the LED sidelight thing for a while and the colour temperature of the 3 sets I've tried has always been a bit more blue than the 6000k HIDs I have fitted.
Then I thought about the light housing itself - the sidelight section has no reflector and is grey (plastic colour) inside. That and the diamond effect of the lens could quite possibly be causing the greyish blue tint I was seeing.
SO! Simple really, what I did was spray the inside of the sidelight bit with white spray paint. Did this on a spare set of sidelights that I'd cracked one of open earlier.
If you haven't already, it's a good time to remove the orange lens and get a silver 21w indicator bulb to remove the tango look from the front of the car. I didn't on these as they're in bad condition and I already have detango-ed ones
Now looking at the pair here, one has been painted and the other I have left standard. The white is quite noticeable - I don't know what this looks like in the daytime on the car as its 11pm now.
In front is the 5 SMD LEDs I use.
Without the white paint:
With the white paint:
You can see a much better distribution of light and in real life, it does look whiter. I briefly tested it on the car (one with paint, one without) and I didn't leave much time for the HIDs to warm up so check back here for my final verdict! The distribution though did look better. If you're using 501's were the LEDs are all forward facing you won't get as good a light distribution, but this would still help (the diamond pattern on the lens will still reflect some light back into the casing)
and work excellent