You can increase the limit further from 20mph/32kph by then using STunlocker to change the wheel size. Downside is that this effects the speed readout and the odometer/trip distances - but the plug in speed boxes like the one you have mentioned work by intercepting and changing the wheel speed...
My suggestion would be to use STunlocker to change your region setting to US, which will raise the speed limit to 20mph/32kph. This is easy and does not effect the speed readout or odometer. I have found the small boost to be sufficient to rarely be running out of assistance on most trails...
the Mountain Tuning looks like a superior solution and would be my first choice as the "proper" method to derestrict via software.
There is also a PLANET3 option available. I am personally not a fan of speed boxes or mechanical devices that alter the signal from the rear wheel as this creates...
The e6100 is rated at 60NM though i am unsure the maximum assist percentage available. 200% sounds a little low and could be a glitch withthe app?
I would bump boost and trail up to 60nm so you have full power/torque available. Set boost to maximum assist percentage and probably leave trail...