I tried changing the rear running and brake lights to red LED..

I installed the LED bulb on one side only so I could compare brightness. The running lights were about the same brightness, but the brake lights were definitely dimmer..

So I took it out..no way am I going to run with dimmer brake lights..

The Toyota tail light reflector design makes good use of the light given off to the side of a standard bulb, but the LED bulb (even one with additional LEDS mounted in a circle pointing to the sides) doesn't work well with the reflector.