The matrix motors are both stock motors from memory, 27t, 24deg timing. If you pull them apart they should have Yok27 on the arm somewhere i think... not 100%. From what i recall when i ran them, the 6.5 was a more Torque based motor and the 7.5 was a High RPM motor... both were actually very competitive in their time (Green Machine and P2K era lol)
The Midnight is a Trinity Stock motor... dont know ALot about them... its non-rebuildable i think?
Hope that helps...
Yokomo * HobbyWing * Sanwa