I have had a few RSB's on my V6 coupe and with a nose heavy FWD car I personally found the thicker, the better. I daily drove my Accord for many years and never felt like the Progress bar was a bad choice, made the car far more neutral and killed body roll as well.
In general the aftermarket for the 6GA was crap, mostly since there was no JDM equivalent of these cars. But there were a few standout companies that made great quality parts, and Progress is one of them. Nothing against Eibach, and 1mm won't be a huge difference if you find it for much cheaper.
Don't forget to get some good endlinks, you can bet the OEM's will not be reusable. Lots of people went with Moog, but even those let me down a couple times when changing them out with proper tools. I haven't looked for 6GA endlinks for a long time so maybe that's all there is still, but if there is something a notch up from Moogs I'd get them. Or Moogs are fine, cheap enough to not feel bad throwing them away.
I imagine you are going to, or already have done, swapped full suspension since you plan to auto-x.