I dug out my Gen1 Dragstrip for a photo-shoot with the new Generations Dragstrip, and found that one side of it was darker like it had been sun-damaged... and so was inside the driver's seat, which is covered by the engine in robot mode. Since my Dragstrip has been in robot mode and in the dark for over ten years (and I'd have no idea if it was ever on display in car mode before that for any lengthy period of time, let alone where the Sun could hit it), it makes me think that it might not take much sun exposure... and can take many years before the colour starts changing.

Like a ticking time-bomb that you can't prevent, and maybe like skin damage, in that it is said that the damage happens when you are a kid before you know or try to protect your skin, and no matter how much you look after it later, the damage has been done... and melanomas can pop up at any time.