This is a very widely misunderstood matter.
It's not a matter of limiting with the Chopper, it's the gearing. The 16 mph Sprint's motor is designed for a 26" wheel, so when it's put into a 20 inch wheel, the speed is reduced by the ratio of 26 to 20. In other words, divide 16 mph by 26, then multiply the answer by 20 and you get that 12.5 roughly.
The Torq is the opposite. It's motor was designed for the 16 mph Quando's 20" wheel, so when it's put into the 28" wheel it goes faster by that ratio, 16 mph divided by 20" and then multiplied by 28" equals roughly 22, the Torq's top speed. Only because that is illegal on our roads is a limiter applied to the Torq to hold it to the legal speed. The other models have no limiters because they don't need them to keep to the law, so there's no limiters to derestrict. These facts don't just apply to eZee bikes, they are true of all makes. Nearly all electric bikes are designed so that the motor's maximum revs on the battery's voltage produce roughly the legal speed, so no limiting is involved.
Another way of looking at this is to think of each motor having a given speed. If it's put into a wheel with a smaller circumference, it goes less far with each turn, in other words, it's slower.
The Torq's limiter stub is often tucked under the other parts of the wiring under the bottom bracket, look for some red insulation, that's on some models. You'll have to remove the insulation on the stub to reveal the shorting link.