Long term value, it all depends on your definition of what "long term" is. In 50 years, both the SP and the SS will be worth good money if kept in great original condition. The SS will obviously be worth more. The biggest difference you'll see in value will be in what I call the mid term. This starts around 5 years after the cars go out of production to about 10-15 years. During this period, most SPs are bargain bin worthless. They're the choice car for street thugs, young 20-somethings, and are about as common as a sunburn at the beach. That being said, they'll still worth more than a 5.7L or an SXT. The reason for the devaluation is mostly due to their sheer production numbers. With lots of cars, you'll get lots of used ones, and lots of those used ones will be ragged out during this time period. It'll drag the market for all SPs down. Those that survive in near new quality to the long term, those will be worth money.
With the SS, it has strong short term value... and in some cases, might even be flippable on day 1 for a profit. Short term is the period starting at delivery to within 5 years of model closeout. This is the period where the cars are still desirable. For a few years... say 2026 or so, there will still be a strong seller's market for late model Hellcats as people who wanted one couldn't get one, and they'll be looking for good used ones. But, after the short term ends, it's a bit uncertain as to what the SS will do. Yes, it's the most rare Hellcat submodel, but most people don't even know an SS exists. They will obviously offer a premium over an SP, but I don't know if there will be a special Super Stock market in the mid term. At worst, they'll mirror the RE/REWB market... whatever that turns out to be. I just think it'll be a hard sell to try and get a premium over a REWB. I don't think the differences warrant a premium. I could be wrong though!
With the SS, it has strong short term value... and in some cases, might even be flippable on day 1 for a profit. Short term is the period starting at delivery to within 5 years of model closeout. This is the period where the cars are still desirable. For a few years... say 2026 or so, there will still be a strong seller's market for late model Hellcats as people who wanted one couldn't get one, and they'll be looking for good used ones. But, after the short term ends, it's a bit uncertain as to what the SS will do. Yes, it's the most rare Hellcat submodel, but most people don't even know an SS exists. They will obviously offer a premium over an SP, but I don't know if there will be a special Super Stock market in the mid term. At worst, they'll mirror the RE/REWB market... whatever that turns out to be. I just think it'll be a hard sell to try and get a premium over a REWB. I don't think the differences warrant a premium. I could be wrong though!