They look it, but they're not. Like I said, it's just the colour. You can see SFA with them in the dark.
Whoooah there neddy.
-That's just as inaccurate a statement as declaring that a petrol engine will always make less torque than a diesel; It's an apples-to-oranges comparison, and actually quite wrong.
Coloured incandescent bulbs are the only bulbs which meet your description. (see the Daniel Stern Lighting site for a more detailed explanation) but it is absolutely inapplicable to LEDs.
Here's what I
THINK you may have meant:
White LEDs are equivalent to a higher colour temperature, and a higher colour temperature gives the IMPRESSION of being 'brighter' because as a light bulb increases in brightness, so too does its colour temperature.
The correct way to measure brightness is in luminous intensisty, specified using the unit 'candela' (or often 'millicandelas which is a 1/000th of a candela).
HOWEVER...
It is perfectly possible to have LEDs which are much brighter than normal incandescent bulbs. Not only that, but they consume less power to create even MORE light than their 'hot-wire' counterparts.
What makes them a poor-swap in terms of luminous intensity is the discrepancy between angular light dispersion. MOST incandescent bulbs radiate light equally in all directions (an exception is the PAR series which stands for Parabolic Aluminized Reflector). LEDs are 'lensed' to concentrate their light and -like the PAR bulbs- concentrate most of their light in a nominally 'forward' direction.
Many vehicle lights ignore much of the 'forward' light of the bulb, and instead gather the 'side' light ejection (like a lighthouse light collector) and direct it in a single direction. The A3 sportback tail light is a perfect example of this -I can't speak for the hatch light arrangement as I've not examined one in person.
Unfortunately there are several other variables which make comparison difficult, but the underlying fact is that if you get enough LEDs of sufficient power correctly lensed, their output will be VASTLY brighter than an equally-powered incandescent light.
ALWAYS, AND WITHOUT EXCEPTION.
Keith