When looking at replacing your stock automotive halogen/incandescent light bulbs with a new LED product it’s important to know the differences as to how the new light bulb will act in the housing you are going to place it in.
For best results the LED color should be the same as the lens color or if bulb is behind a clear lens, use the appropriate color for turn and brake light functions. As an example: a red lens will filter out all but the red portion of the light so if the light is all red, none or very little light will be blocked by the lens. The light from a White LED contains very little light in the red portion of the visible spectrum so most of the light would be filtered out by a red lens.
Brightness of LED Car Bulbs
Standard LED bulbs are generally not as bright as standard incandescent bulbs, they have many advantages over filament bulbs (longer life, faster on/off times, lower power consumption, more vivid colors) but brightness is not one of them. They are generally not as bright but some of them with large numbers of LEDs, will appear brighter than filament bulbs. As an exception, GTR Lighting TW6 LED car bulbs are as bright or brighter than most standard filament car bulbs. The light is distributed differently so they can appear brighter in some applications and not as bright in others, it depends on the size and shape of the bulb housing and reflector.
Most LED bulbs emit light like a flashlight, all out the end. Regular filament bulbs emit light from the end and all sides, so they will be better suited for some lighting applications than LED bulbs.