I have the Fet2 e-wire choke. I used the regular Fet and while the adjustment was great i hated the voltage choke. Now the ewire is just like a wire choke and i find myself using it to just tame a car like traction control.
I can also attest to the strength of the design. I will admit to hooking the controller up wrong with no ill effects and even tripped the track main breaker. I just swapped the wires and off i went.