US wise there are no 300 with STP. I am sure the 300 SRT has the STP. but they appear to all be export cars in UAE or Australia. My thought are to find a 2017 Charger SRT with the Safety Tech Package. That would be the most similarly equipped car. Thanks for the suggestions. When I get a chance I will play with it.I honestly would ask a member with a 300 and STP (not sure if that combo exists) to take a read of their BCM to find the chassis number. Otherwise you can try going through the list of chassis types that have 5ZR + SDB in alfa. Although there are a lot of number that have no sales codes next to them which actually might be the right one. For example, 77 is the number that gave me STP. If it were me I would try the following numbers:
26 (why because non-STP RT was 76 and the STP version was 77 - jumps by 1)
35 (why because a non-STP STX charger is 24 but a STP version is 34 - jumps by 10)
77 (why because it works for a auto and manual challenger RT)
If these don't work I would then start with the types that have the 4 door and heavy duty suspension sales codes.
Hopefully going through the numbers won't cause any irreversible damage. A member on the challenger forum tried some numbers that did not work (he even tried a scat pack chassis type) but was always able to go back to his original chassis type without and ill effects. BUT there is always risk.