The jams are the base color without the pearl. Honestly, if you are going to keep it yellow I would go with the original color with the pearl, but thats me. This color looks great when fresh as you said. I dont quite understand what your guy is getting at with "oxidated" . It is a base clear paint, the clear comes off and paint fades. I think the pearl paint loses more of its "magic" when faded as opposed to the straight colors that is probably true. I have a yellow just like you and I have a Cherry Red Pearl convertible that was just painted and all of the non-z people swear it is a different color now (everyone loves it) when really it was supposed to be the color it is now all along. After 17 years it is not the same color as it started is all. When the Z32 fist came out a yellow TT was the car they used for promos at the time (cars shows etc.) because it was the most visually striking regardless of your preference for the color or not.
