On the Stromer all the torque works on the rear wheel and propels it forward. With middle motors on the other hand, the torque is initiated in front of the derailleur and transmitted through it. It is thus difficult to compare a mid-mounted motor with a rear wheel hub motor.
Stromer gives the nominal torque in each motor specification. The nominal torque is the torque that can be achieved on a sustained basis. Maximum torque is always significantly higher.