Well....since no one cared to offer any suggestions, I am moving forward into this "uncharted country" myself and will advise findings.
I have purchased 2 NRG FRP-310s ($165/ea AutoPartsDealer.com). This is the medium sized seats. I picked the mediums over the large because I was worried the shoulder wings on the large seat might hit the windows.
They arrived yesterday and I have not installed them yet pending finding some rails & sliders. I plan to try a junk yard first to see if I can somehow get some off a wreck. The last time I looked however, this did not seem like an easy task. GTFour77 fabed up his own, but I don't have a welder.
In a trial fitting just to see if my fat arse (40 inch waist) would fit in them, it was snug but no worse than the factory seats with the bolsters moved in for autocrossing. As you know, the factory seats are very good by themselves, however they weigh 50lbs each. I can remove 50lbs with this swap under SCCA rules, and more if they ever decide to remove the 25lbs minimum.
Initial quality appears good although I am spoiled by the very comfortable factory seats. There appears to be some flex in the shoulders, but it wasn't mounted to the rails so it might be a little better/stiffer when the base is mounted.
Will update again after I find some rails and get them installed.