Nice disassembly video comparison! Where in Europe is Varstrom? (he speaks perfect Amer english).You can buy torque sensor from PSW, but it is expensive. I would buy new motor and keep old one for spares.
59km/h? 1700W output? You really need a motorbike, or electric scooter not a bicycle.
Disassembly:
Here's a video of him installing a TSDZ8 into a carbon frame. total weight 17 kg (less pedals).