I think there is a lot of work performance wise that you will need to do to get anywhere close to being able to call it an SRT. Even then it won't be a true SRT. It's my personal opinion, but if it didn't come from the factory as an SRT then it shouldn't be badged as one later. No matter what mods you do to it.
As for the suspension of the 06 Charger RT with R&T package.... that is not the SRT suspension. It comes with the sewlf leveling Nivomats on the rear. The SRT doesn't. It has bilstien shocks and stiffer springs.