Some pics it looks like the miata one (almost mustard), some of them looks very light (lemon).

 

There were two different yellows available on 2002 Miatas. The SE metallic yellow was, IMHO, nasty. In our house, it's known as "French's Classic Yellow" or "Mustard Mica."

But if you ordered online, you could get a regular 2002 Miata in Vivid Yellow, which is the same as the Protege5 used in all the "Zoom, zoom" commercials. That's a gorgeous color. I know because we have one sitting in the garage right now. :D

I'm hoping the Lightning Yellow is closer to the latter, obviously. One good sign is that it's NOT a metallic color.

 

I've seen the Yellow RX-8 in person and right next to it was a yellow P5. The Yellow 8 is much more lighter than the P5 color, I refer to it as the color of a yellow highlighter pen. I personally don't like it as it does not bring out the features of the car very well. I also saw the red one. All I can say is WOW! :D It's a metallic red slightly darker than the Classic Red on the Miata, but not maroon. Needless to say, that is the color I choose!

Later,
K

 

I saw the yellow rx8 prototype in person at the Toronto Auto Show and it is absolutely gorgeous!!! If I remember correctly Mazda called it vivid yellow and I looks like the yellow you find on Ferrari and Lamborghini – OUTSTANDING!!!!!!

Mine will be the yellow with a black leather interior.

 

Indeed, Vivid Yellow is a fabulous color, but judging by ZZOOMM's post it seems that the Lightning Yellow they're using for the production models is somewhat lighter.