I'm definitely getting the Center Diff but I'm most likely going to get the new RB TM523 engine. Bi-turbo Crankshaft, Turbo Button, and 7+2 Port design.
i wish i would have read this bedfore i ordered a sirio trinity .23 what modifications should i make to the drivetrain to get the extra power to the ground?
A really strong CVD set. I'm using T Bonz right now, and they're sweet. I'm waiting to hear back from TiR about their titanium CVDs. You could also strengthen your diff with aluminum cases and cups.