These simply don't produce the same light levels as a 21 watt indicator
bulb in the normal reflector.

Euro car lighting parts must be 'E' marked to conform with those regs. And
non of these replacements are - simply because they can't produce the
correct spread of light at an intensity to replace a 21 watt filament
type. The other type of LED replacement with 5mm leds 'firing' forward do
just about produce the same intensity - but only over a very narrow angle.

For safety lights like indicators etc where a wide viewing angle is
required these things are positively dangerous - they can't be seen in
bright daylight.

Take a look and tell me what you think - these seem pretty well designed
to widen the viewing angle:
http://www.virtualvillage.co.uk/Items/002510-030?

For a start there are no direct replacement LEDs for units designed for
tungsten - the optics on these lights is optimised for a point source
filament. And for things like indictors this is a very real problem in
sunlight etc - the LED replacements simply won't be as bright, or have the
same viewing angle. And it's not just a slight difference either. There
are currently no LED replacements that meet the specifications required by
law in Europe. Completely new lamp units designed from the start for LEDs
are a different matter.

They will also confuse the failed bulb warning system.

Can anyone advise me if fitting after market LED bulbs in indicators,
side adn brake lights confuse the onboard computer?
I prefer the more responsive light they offer but don't want the car
dinging me about dead bulbs!

I've a 2001 E39

Thanks
David