I've raced Nastar with a variety of skis, ranging from my 175 Volkl Tigershark 12"s to a 202 SG ski. It really depends on the mountain you ski at and how they set the course; I've seen some pretty straight NASTAR courses, and yet I've seen a few where you need to turn here and there. I honestly preferred my 187 (really a 185 when measured) Volkl Racetigers, for both NASTAR and cruizing around the mountain. I have had handfuls of different Racetigers, in sizes and flexes. I found the 180's to be too soft and too short for me at times, and I am 5'9" 155#. 190s worked for me as well, but not as good as the 187 (185) skis. I've had 4 pairs of 187s in the past two years (got to ski 3 of them), and loved every one. I recall many good days flying down Okemo's World Cup and Chief trails. Fun stuff. The 4th pair is sitting in my room, new in wrapper, looking for a new home. I've been considering just mounting them up, and having them be the odd pair out since I ski on Nordica now, but the powers that be may get me a pair of Nordica's. Either way, they are by far my all time favourite ski that I have owned. Period.
And to quote you saying "I race a few weekends a year, however love to bomb down nice groomed slopes doing high speed carving all day long" - this is exactly what I love to do. The only time I ski on my SL skis is when I have to, or when it's a Sunday at a mountain like Pat's Peak or Killi, and skiing on something longer could kill someone. Even then, the GS skis come out for a few runs.