Etarga's red tail/brake bulbs and amber turn bulbs, on a 1980SC with stock taillight wiring.
Naked tail light bulbs (incandescent on the left, LEDs on the right, covers removed):
Naked tail and turn bulbs:
You can see that the basic brightness of the LED bulbs is very similar to the stock filament bulbs, but they have a good clean red/amber color stock. Visually they were the same brightness, but the camera makes the white bulbs seem brighter, because it picks up and accumulates more wavelengths of light. This is a problem when you make a picture like this:
Which is all filament on the left, LED on the right, with covers on. The camera makes the filament bulbs seem might brighter (and whiter) while visually, the LEDs were equal in brightness, and had a better color, or punch to them.
Now, equal exposures (1/4second) with equal aperture, and fixed focus. Filaments on the left, LED on the right, covers on, tail lights only:
Then brake lights:
You can see how the license plate illumination is equal, which shows that I'm not trying to scam anyone.
Then, same deal with the 4-way flashers on (took a few so as to get one that actually picked up a full flash during the 1/4second exposure):
So, all said and done...
1) The LEDs are not significantly brighter, if at all, than good fresh filament stock bulbs.
2) The colors are much better than stock bulbs, and the sharp on/off of an LED adds some visual punch to things like the turn signal.
3) The flasher timing was exactly the same with and without the LEDs. NOTE...add LEDS to the FRONT and your flasher timing will be a mess.
4) If your lens covers are not in 100% condition (like mine), then the LED prevents that white light leak around the edges, and gives a cleaner look.
5) I do not know the amp draw of these bulbs, but it should be lower than the filament bulbs, which means less load on your wiring, switch, connections, etc which is always good in our cars.
I'm happy with them.