Well, because it has a RR layout, the standard engine and less body roll I think there's not REALLY a need fot it. I drove a normal 993 with a LSD and it felt a little bit more twitchy when you hit the gas in corners.
There were actually a couple hundred shipped to America in 1993. It was
supposed to be sold only in 1993, but Porsche got so many orders for them
they continued producing the RS America through 1994. You are correct
though, only 84 were sold as 1994 models. The 1994 models had back seats,
and the 1993s did not.