I tend to be a torque kinda guy - gimme a big diesel, big v8, lots o' torque and I'm happy!
I'm running an MT12.
Really, my advice was boiling down to "stick with what you know" - the Rossi motors are good motors and you already know the Mugen motors so I would stay with them.
The other part of my advice was to stay away from that Evil Empire that is Trinity.
Hope it works out well!