YES!!
I can finally shed some light on the whole Silvia club's thing.
Starting with the SR20 equipped Silvias, Nissan released the "Art Force" editions. One was oriented towards performance (the Silvia Club's) whereas another was centered on luxury, (the Silvia Diamond's). The Club's could be ordered on any hardtop Silvia, the J's,Q's,or K's, while the Diamond's could be had on all those models, and when the limited edition Silvia convertible came out, it is rumored that the Diamond's package was standard.
I don't know yet what specific parts seperated the packages except what I have already said.
The badges were different from the standard badges, as they were chrome, and had a little diamond or club as part of the badge. The diamond's badge is easy to get, which is ironic, as most ppl don't know the diamond's package existed.
Here's a K's diamond badge:
and here's the cover of the Silvia Art Force editions brochure:
