No limits like the Demon. Dragcr has also said the suspension is not the same as the Demon
This is a good article comparing Demon, SS and RE
https://www.caranddriver.com/news/a33015174/2020-dodge-challenger-srt-super-stock-revealed/
So the remaining diffs I see (besides limited production for the Demon) are:
Hood
Race fuel tune (840Hp)
Demon Crate
9.65 ET vs 10.5 ET (per Dodge). Despite "only 33hp diff" and maybe -20lbs (for equivalent single seat cars). The only thing I can think here is the suspension isn't quite the same for the SS. Also, Demonology had multiple dynos using Boostane only showing ~902hp at the crank on his Demon (not 840) so the hp diff may be more than +33 between the 2.
Lightening throughout (-220lbs if u got a 1 seater Demon). Though much/most? of that 220 can be attained in RE and SS by going 1 seat?
Badging, Demon nittos, and some external color differences
I'm sure DRAGRCR has a few more nuanced differences. I seem to remember RE (and maybe SS?) having hiccup during WOT that the Demon does not have.
Still a nice option for those who missed on Demon. My only concern is that the only variant not depreciating and still commanding above MSRP is the Demon, so longer-term, it might make sense to buy a used Demon than a new $100-105K SS.