Yeap - sounds like fading paint to me as well.
I saw an early Cupra R the other day and decided to follow it (a little bit
). I noticed the back was a richer yellow to the right hand side and it was definitely a fade job.
I reckon the yellows and reds will fade more so than the silver/grey and blacks. Although blacks show stonechippings a lot more. I guess the best thing to do is get a silver/grey one although I must have BLACK.
Just stand it in the sun with the darker yellow towards the heatrays and I am sure it will even itself out. Just like a suntan.
Cheers - Cobraman