If you have white LED's there is bad news that comes with that. If you have true white or "super" white LED's, they produce an utraviolet light that causes photodegradation to the resin that makes up the LED, also, The "Stokes shift" is longer and requires more energy and hence is less efficient, and creates more heat than an RGB LED, which is how it creates a whiter, and brighter LED. That's why white LED's don't last that long. It has nothing to do with the "quality" of the LED. An RGB LED will last 3x's longer, and the new amber LED's will also. I have a feeling that is why Lexus used a color LED for those displays, as they are very inaccessable for replacement. The instrument cluster LED's are much easier to access and therefore they felt ok with using them there. But that is only an opinion. The only answer I know of that addresses this problem just came out, but it's not a true white LED. In fact it looks more like an incandescent light somewhere in the 3000-3500 K light spectrum range. ( which would have a faint yellowish to it.) But even so, the life span of a white LED or NUV LED, is in the practical range of 50,000 hours of continuos life, a little shorter in a car where voltage fluctuates and spikes. If you want to make your LED's worry free and also make all your other electronic equipment last longer, you might want to consider a Hyper voltage system. You can check it out for yourself.
My opinion???, still looks great, and I would do it anyway also. I just finished getting the right load resistance for the NUV LED's or white LED also. It's 3.2 volts. HHHHmmmmm, maybe in a few weeks....
I've just talked with my friend...
3000-3500k would be more of yellow color.. not a warm white..
Warm white would be more around 4000-5000k....
He can get from warm white 4000-5000k 6000k-7000k cool white and like 8000k bluish white...
There is different color temperature for like white LED.... even though they have shorter life, it will out last the car.....
Many of the new white LED has improved alot.. so there is no need to worry over white LED...
Also many of the electronics on the car is voltage regulated and current regulated... the voltage spike has very little issue..
I've seen so many cars comes with white LED for the gauge cluster these days... Example like Toyota camry, Honda accord, civic... also new Scion xD comes withe white LED.....
So white LEDs no longer an issue with reliability...