Royal Purple Synchromax Trans oil. Ok. I apologize ahead of time. This issue has come up b4. But I desire definitive answer . . . if there is one. Many say its not good for the 2008 Mustang GT. I read this S197 model is a T-3650 transmission . . . not sure if this is correct. Many say its good for this car. Throughout this forum, I read some good stuff and some bad stuff. Many seem to say use Mercon 5. Final scoop...RP Synchromax good or bad?? I just want to make sure it won't screw up the car and is not worse then factory recommended fluid. Thoughts? Yes, I already ordered it and LMR won't cover S&H if I return it. Lol.